e-STUDIO350/450 DEVELOPMENT SYSTEM 12 - 2 November 2003 © TOSHIBA TEC
12
12.2 Functions
(1) Toner cartridge drive unit / Toner cartridge detection switch
The toner cartridge is filled with toner. The toner motor drives the cartridge to supply the toner to the
developer unit.
The toner cartridge detection switch detects whether the toner cartridge is installed.
(2) Developer unit
(a) Developer material
The developer material is made of a mixture of the carrier and toner.
The carrier is an electrical conductive ferrite whose size is 30µm to 100µm. The toner is a resin
particle whose size is 5µm to 20µm.
The developer material needs periodic replacement since its quality is deteriorated by long use.
(b) Mixers-1 and -2
Friction is generated by mixing the developer material. The carrier is charged to (+) and the toner
to (–), and the image is formed on the drum surface by the static electricity caused by the friction.
(c) Developer sleeve (Magnetic roller)
This is an aluminum roller with a magnet inside. The magnet works to absorb the developer
material and forms the magnetic brush. The magnet is fixed and only the sleeve around is
rotated. This rotation makes the magnetic brush of the developer sleeve sweep over the drum
surface and perform development.
(d) Doctor blade
Doctor blade controls the amount of the developer material transported by the developer sleeve
so that the magnetic brush of the developer material contacts with the drum surface properly.
(e) Auto-toner sensor
The carrier and the toner (toner density) in the developer material should be always fixed to a
certain ratio to output normal images. The auto-toner sensor detects the inclusion ratio of the
toner in the developer material by using a magnetic bridge circuit. When the quantity of toner
becomes insufficient, the toner motor is driven to supply the toner from the toner cartridge.
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