Panasonic UF-6300 Service Manual page 179

Development
This development process uses a conventional method, where toner coats a Development Roller and
transfers to the latent image on the OPC Drum. In the Toner Cartridge, the (mono-component) toner is
negatively charged by the friction between the rotating Development Roller (Mag Roller) and the
Developing Blade. This combination and the rotation of the Mixing Blade transfers the toner from the
reservoir and forms a brush effect on the Mag roller. Where the magnetic brush lightly touches the OPC
Drum, the negatively charged toner is attracted to the latent image on the drum, forming a mirror image
of the original on the drum. Any remaining toner is removed from the Mag Roller by the Developing
Blade and is recycled back into the toner reservoir. A bias voltage of approximately 1.65 kVACp-p at
1.875 kHz, riding on a -300 VDC bias is applied to the magnetic brush to achieve maximum print quality.
The Toner Sensor (513), a magnetic sensor, detects the remaining quantity of toner in the Toner
Cartridge. When the "TONER" lamp starts to blink, there is still enough toner left in the cartridge to print
100 pages (based on ITU-T Image No.1). When the toner runs out, the display will show: "OUT OF
TONER & INFO CODE 041" and the machine is disabled from printing any copies.
The Toner Cartridge consists of OPC Drum, Bias Charge Roller, Development Roller, Developing
Blade, Cleaning Blade, Mixing Blades and Toner Waste Box. The OPC Drum is an aluminum cylinder
coated with an OPC (Organic Photo Conductor) sensitive material. This surface is photoelectric (retains
the charge in the dark and releases the charge in the light). The potential differences on the surface (a
static latent image) form a printed image. The Bias Charge Roller provides a uniform charge on the
OPC Drum surface. The Development Roller supplies toner to the drum by rotating over the magnet.
The Developing Blade evens the toner on the Development Roller surface and also charges the toner
by friction. The Cleaning Blade cleans by scraping the remaining toner off the OPC Drum surface after
transfer.
Transfer and Separation
As the paper is fed between the OPC Drum and the Bias Transfer Roller (BTR) (604), a positive charge
of approximately +3.0 µA steady current is applied to the backside of the paper by the BTR. The toner
particles are attracted away from the drum towards the surface of the paper. During cleaning, the BTR is
charged to approximately -1500 VDC to repel toner on the OPC Drum and prevent toner from being
attracted to the BTR. After transfer has occurred, the paper passes over the Discharge Plate (612) in
the Transfer Guide (601), reducing the difference of potential between the OPC Drum and the paper.
The stiffness of the paper causes the paper to separate from the drum.
Cleaning
After transfer, some toner may remain on the surface of the OPC Drum. A Cleaning Blade scrapes the
OPC Drum surface, and the removed toner is moved into the Toner Waste Box, inside the Toner
Cartridge.
Laser Unit
Beam Detection Sensor
LD PCB
Laser Diode
Bean Detection Lens
Collimator Lens Aperture
179
F Lens
Tetragon Motor
Cylindrical Lens
Laser Housing
Tetragon Mirror