Brother HL-3450CN Service Manual page 73

CHAPTER 4 STRUCTURE OF SYSTEM COMPONENTS
7
The second transfer process is where the toner image on the transfer drum is transferred
onto the transported paper.
(1) Second Transfer Structure
i) The transfer roller for the paper transfer is located as shown in Fig.4-8.
ii) The transfer roller is normally kept out of contact with the transfer drum until the
iii) The transfer roller is positively biased by the power supply THV.
iv) The transfer roller is in contact with the transfer drum only in the second transfer
v) Transported paper passes between the transfer roller and transfer drum.
(2) Second Transfer Process (Refer to Fig.4-21.)
i) Paper is transported and is synchronized with the transfer drum.
ii) The transfer roller operates and is synchronized with the transported paper and is
iii) The transported paper passes between the transfer roller and transfer drum.
At this time the positive high voltage (THV) is fed to the transfer roller.
iv) Negatively charged toner on the transfer drum is moved to the positively charged
v) The transported paper with the toner transferred to it is moved to the paper
Paper discharger
Transfer roller
VAC
Second Transfer (Paper)
second transfer process starts.
process.
in contact with the transfer drum through the transported paper.
paper.
discharging process.
Transfer drum
THV
VAC: Power supply for paper
discharging
Toner image
THV: Power supply for transfer
roller bias
Paper
Fig. 4-21
4-20