Toner detection

The product uses a nonvolatile memory tag built into the print cartridge. Print-cartridge detection happens when the engine controller detects the presence of a genuine HP print-cartridge that contains a memory tag. Toner detection happens as the engine controller reads or writes the data that is stored on the memory tag. The engine controller renews the information in the prescribed timing and reads or writes it from or to the memory tag.

The engine controller commands the memory tag to read or write with the following conditions:

●Read

◦Power is on

◦The cartridge door is closed

◦A command is received from the formatter

●Write

◦A page of media is printed

◦A command is received from the formatter

When the engine controller fails to read or write three times in a row, it determines that the memory tag is abnormal and sends a cartridge memory abnormality warning to the formatter.

Figure 1-25Print cartridge memory tag

32 Chapter 1 Theory of operation

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