HP LaserJet 5000 Service Manual - Page 98

Toner Cartridge Detection The Toner Cartridge has a toner sensor. The circuit compares the output value of the developing AC bias and the output value (ANT) from the antenna inside the cartridge, and outputs the toner detection signal. The CPU detects the remaining toner level and the presence of the cartridge when the developing bias is applied to the developing cylinder. The remaining toner level is always detected when the developing bias is applied. The presence of the cartridge is detected only when the developing bias is applied during the initial rotation. DC Controller System The following systems and functions are controlled by the DC Controller PCA: q DC Power Distribution (+3.4 VDC, +5 VDC, +24 VA) q Laser and Scanner Drive q Paper Motion Monitoring and Control (photosensors and flags) q Clutches (tray pickup and Tray 1 feed) q Engine Test q Motors (Main Drive, Scanner, and Fans) The operation sequences of this printer are controlled by the CPU of this circuit. When the printer power switch is turned on and the printer enters the standby mode, the CPU outputs the signals to drive the loads such as laser diode, motors, and solenoids, based on the print commands and the image data input from the external device. EN Power Supply System 5-7