Covering the sensor window, adjusting or modifying the timer wheel…
None of these work for me.

But, the internal life timer does:
1 Open the front cover of the printer
2 press and hold the cancel button
3 press the reprint button while still holding cancel

Now it shows the toner life reset menu.
H is for High-Yield carts, and S is for Standard Life carts.
Cursor to the correct one and use OK to reset it.

FYI… Pressing the "Go" button and the up arrow gives you the parts life reset menu (drum, laser, fuser, etc.)

Also, I found that my waste toner tray was pretty much full.
That probably has to do with why there’s so much toner overflow inside.
There are 2 small panels that can be removed that allow the toner to be drained out.
It’s VERY messy, and may have local waste rules, so plan accordingly.

HL4070CDW
xaminmo