TD Sensor (Toner Density Sensor)
The TD sensor [A] is a non-contact type sensor that detects the toner density in the development unit. This sensor is attached under the development unit. The amount of toner that is added to the development unit depends on the toner density detected by the TD sensor.
In the predecessor models (MP C6502/8002, Pro C5100S/C5110S), a HST sensor is used to detect the toner density. This machine uses the μ sensor, which is a non-contact type sensor, instead of the HST sensor. The HST sensor can directly detect Vt. On the other hand, the μ sensor cannot detect Vt directly. The output value of the μ sensor is a counting value which corresponds to the frequency. Therefore, the detected counting value needs to be converted to Vt to use for toner supply control.
The TD sensor has an ID chip. The ID chip contains information specific for the machine type, development unit information, rotation running distance of the drum, and information for image density control.