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II-30
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 non-magnetic toner. The developer roller made of
conductive rubber and the supply roller made of conductive sponge rotate on each
other. The toner is charged and carried from the supply roller to the developer
roller. Thus, the toner is adhered to the developer roller and conveyed to the drum
with its thickness made even by the blade. The toner is nipped between the
developer roller and the drum and developed on the latent image.
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 devel oper roller to the drum.
Fig. 2.34
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.
(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.
Transfer roller
Blade
Toner
Auger
Develop housing
Supply roller
DC-bias
Developer roller
Drum
Cleaner roller
Erase lamp
(b) Cleaning process [ON]
(a) Transfer process [ON]
Summary of Contents for HL-720
Page 1: ...SERVICE MANUAL MODEL HL 720 730 730Plus R LASER PRINTER ...
Page 36: ...II 19 1 3 10 Engine I O HL 720 Fig 2 21 shows the engine interface circuit Fig 2 21 ...
Page 37: ...II 20 HL 730 730Plus Fig 2 22 shows the engine interface circuit Fig 2 22 ...
Page 61: ... Fig 3 18 2 4 1 1 1 ...
Page 92: ...SERVICE MANUAL MODEL HL 760 R LASER PRINTER ...
Page 109: ...II 8 1 3 4 DRAM Two 4M bit DRAMs x 16bits are used as the RAM Fig 2 6 ...
Page 113: ...II 12 1 3 10 Engine I O Fig 2 12 shows the engine interface circuit Fig 2 12 ...
Page 114: ...II 13 1 3 11 Paper Feed Motor Drive Circuit Fig 2 13 ...
Page 133: ...Appendix 2 Main PCB Circuit Diagram 1 3 CODE UK3227000 B48K272CIR 1 3 NAME ...
Page 134: ...Appendix 3 Main PCB Circuit Diagram 2 3 CODE UK3227000 B48K272CIR 2 3 NAME ...
Page 135: ...CODE UK3227000 B48K272CIR 3 3 NAME Appendix 4 Main PCB Circuit Diagram 3 3 ...