Brother 1270N - Manual (Page 67)

CHAPTER 3 THEORY OF OPERATION
3-25
2.3.2 Toner sensor
Detects if there is toner in the toner cartridge. The toner sensor at the left side emits light
through the window on the left side of the toner cartridge, then the toner sensor at the right
side receives it when the toner is low. They also detect whether or not the drum unit is
installed. (The toner cartridge is installed in the drum unit.)
Fig. 3-33
2.4 Drum Unit
2.4.1 Photosensitive drum
Generates the latent electrostatic image and develops the image on the drum surface.
2.4.2 Primary charger
Forms a uniform charge on the drum surface.
(1) Corona wire
Generates the ion charge on the drum.
(2) Grid
Spreads the ion charge evenly over the drum surface.
2.4.3 Transfer roller
Transfers the toner image to the paper from the drum surface.
2.4.4 Cleaner
Removes the paper dust or dirt on the surface of the photosensitive drum.
2.5 Toner Cartridge
Develops the electrostatic latent image on the photosensitive drum with toner and forms the
visible image.
Toner sensor
(light emission)
Toner sensor
(light reception)