HP PageWide 774dns, 779dns, 780dns,
785zs, 785z+, E77650dns, E77650zs,
E77650z+, E77660dns, E77660zs,
E77660z+, P77940dns, P77950dns,
P77960dns - Printhead wiper does not
reset automatically after installing a new
printhead wiper
ish_4596353-4596399-16 | For HP And Channel Partner Internal Use
Last Modified Date: 2021-09-16
Learn what to do when the UI/Supplies Status indicates that the percent remaining is not
reset to 100 percent on a newly replaced printhead wiper.
Issue
When installing a new printhead wiper, the remaining life of the printhead wiper does
not reset to 100 percent (the UI/Supply Status shows the remaining life at -1
percent/Low/Out for the printhead wiper to be replaced and does not reset with the new
printhead wiper replacement).
Background
The design of the printhead wiper and how firmware determines the state of the wiper is
completely mechanical. If a printhead wiper is manually replaced, the printer firmware
is unaware of the replacement and is unable to update the status. It will ONLY update
the status when following the printer instructions on the control panel.
The wiper is designed with an arm that will protrude from the back of the wiper in three
positions. Because there are only three positions, the exact amount of wiper material
remaining is an estimate until the arm extends to the next position.
A new and never installed wiper will have the arm fully retracted AND two prongs
sticking out on the opposite side of the wiper.
1. A new printhead wiper assembly
2. The two prongs are sticking out on the left side and will trigger a reset
3. The arm is fully retracted
1. A partially used printhead wiper assembly
2. No prongs are sticking out on the left, and a reset will not be triggered
3. No prongs are sticking out on the right, and a reset will not be triggered
1. A depleted printhead wiper assembly with no fabric left
2. The printhead wiper has no prongs sticking out of the left side
3. The plastic arm is sticking out all the way, indicating that the printhead wiper is
depleted and triggering the wiper replacement required message
Affected printers
HP PageWide Color MFP 774dns
HP PageWide Color MFP 779dns
HP PageWide Enterprise Color MFP 780dns
HP PageWide Enterprise Color Flow MFP 785zs, 785z+
HP PageWide Managed Color MFP E77650dns
HP PageWide Managed Color Flow MFP E77650zs, E77650z+
HP PageWide Managed Color MFP E77660dns
HP PageWide Managed Color Flow MFP E77660zs, E77660z+
HP PageWide Managed Color MFP P77940dns
HP PageWide Managed Color MFP P77950dns
HP PageWide Managed Color MFP P77960dns
Possible solutions
There are multiple potential solutions. The following solutions are listed in order of
complexity.
Note:
DO NOT replace the printhead wiper before the printer instructs you to or if the wiper
has greater than 5 percent life remaining. Replacing the wiper too early wastes material
and might create an incorrect printer status.
HP recommends replacing a printer wiper with a new unit only. Never use a used printer
wiper.
Do not rush through the on-screen instructions
Slow down. Follow the control panel instructions for replacing the wiper. Follow all the
instructions WITHOUT rushing through all the steps. Take your time and wait for the
next instructions. Do not skip forward in the process.
Use the printer to see if the status updates on its own
The printer status will often update over time. Normal usage over a few hundred pages
of printing might cause the status to refresh and to display correctly.
Sometimes it will take more than a few hundred pages. When the printer wiper arm
moves to the next position, the firmware detects the change and typically updates the
wiper status.
Do not turn the printer off or manually replace the wiper (T-20 method)
This method is only to be used when a wiper is racked (crooked or stuck) and cannot be
removed or loaded correctly by following the control panel instructions.
If a printer’s wiper has been replaced with this method and the status is not
updated, follow these steps:
1. Turn off the printer and remove the new wiper manually.
2. Manually install the original wiper, or a modified wiper with the mechanical
status arm fully extended.
3. Turn on the printer and if not prompted by the printer to replace the wiper, go
into the control panel menu, and start the replacement wiper steps.
4. Follow all on-screen instructions for removing the old wiper and installing the
new wiper again. Take your time, DO NOT rush through the steps.
If the printer wiper is currently installed but racked, follow these instructions:
1. Turn off the printer and remove the wiper manually.
2. Manually install the original wiper, or a modified wiper with the mechanical
status arm fully extended.
3. Turn on the printer and if not prompted by the printer to replace the wiper, go
into the control panel menu, and start the wiper replacement process.
4. Follow all on-screen instructions for removing the old wiper and installing the
new wiper again. Take your time, DO NOT rush through the steps.
5. When the status of the printer wiper is reset, you may turn off the printer and use
the manual method to remove and reinstall the wiper if needed.
