II - 20
2.5.3
Developing
Developing causes the toner to be attracted to the electrostatic image on the drum
so as to transform it into a visible image.
The Developer Consists of the magnetic carrier and the magnetic toner. The
developer makes the magnetic brush on the developer roller which includes the
rotatable magnet roller. The magnetic brush softly rubs the drum, and then only the
toner developed on the latent electrostatic image.
The carrier particles are attracted to the developer roller.
The toner receives a positive static charge as the toner particles rub against the
carrier particle, rotating developer roller, and trimmer blade. Electrostatic field
between the drum and the developer roller, which is DC-biased from the High
voltage power supply, makes electrostatic potential to attract toner particles
from
the developer roller to the drum.
N
N
N
N
S
S
S
S
Carrier " "
Toner " "
Transfer Roller
(a) Transfer process [ON]
(b) Cleaning process [ON]
Cleaning blade
Erase lamp
DC-bias
(b) Cleaning process of transfer roller
If the toner is not transferred onto the paper perfectly due to jamming etc., it is
possible that the toner adheres to the charge transfer roller. The transfer voltage
charges to positive voltage during non transferring process.
Therefore the transfer roller is cleaned by returning the positive charged toner
adhered on the transfer roller onto the photo-conductive drum.
2.5.4
Transfer
(a) Transfer process
After the drum has been charged and exposed, and has received a developed
image, the toner formed image is transferred onto the paper , applying the negative
charge from the backside of the paper. The negative charge to the paper causes
the positive charged toner to leave the drum, and adhere to the paper. As a result,
the image is visible on the paper.
Fig. 2.27
