HP color laserjet 2550 series Manuale Di Servizio
The developing rotary/toner level detection PCB uses an LED (light emitter) and a
photodiode (light receiver) to determine the toner level in each print cartridge.
photodiode (light receiver) to determine the toner level in each print cartridge.
Figure 4-28.
Print cartridge
Imaging-drum E-label
The E-label is nonvolatile memory, which is built into the imaging drum and stores usage
information. When the imaging drum is installed in the printer, the E-label makes constant
contact with the E-label reader. The E-label reader sends memory information to the dc
controller, which updates the information and sends it back to the E-label.
information. When the imaging drum is installed in the printer, the E-label makes constant
contact with the E-label reader. The E-label reader sends memory information to the dc
controller, which updates the information and sends it back to the E-label.
The dc controller instructs the E-label to read information when:
●
The printer is turned on.
●
The top cover is closed.
●
A command is sent from the video controller.
The dc controller instructs the E-label to write information when:
●
A specified period occurs during printing.
●
A command is sent from the video controller.
94
Chapter 4 Theory of operation
ENWW