Toner-cartridge detection This printer has cartridge detection and toner-level detection. For the cartridge detection, the CPU checks the voltage of the cartridge detection signal (CRGSNS), which is a feedback signal for the primary charging. The CPU checks the voltage of the CRGSNS signal several times while the primary charging AC bias is applied to the primary charging roller. When the average of the voltage is 1 V or less, the CPU recognizes a "cartridge out" situation. Cartridge memory This memory is built-in EEPROM in the cartridge, so that the printer is capable of detecting the cartridge conditions.
Read/write of the cartridge memory is performed by the memory controller board through the antenna unit. The cartridge information read by the memory controller is updated by the engine controller and written to the memory. The read/write of the memory is implemented when the memory controller board receives a command from the engine controller board. The engine controller instructs the memory controller to perform read/write at the following timing. Reading timing ! When the power is turned on ! When the door is closed ! When the engine controller receives a command from the formatter Writing timing ! When printing is completed !
When the engine controller receives a command from the formatter The memory data sent from the memory controller also contains the error status that has occurred during read/write operation. When error status is sent, the engine controller attempts to read the operation four times. If the error status is not cleared after the operation, the engine controller determines one of the following error conditions: sub-CPU failure, memory data abnormality, or memory access abnormality. CAUTION Do not remove the toner cartridge when the top cover interlock is overridden. Cartridge memory will be disabled. Figure 10. Cartridge memory 94 Theory of operation EN