Print Process; Electrostatic Latent Image Formation Block - Canon 3370 Series Service Manual

Chapter 2
When the engine controller receives print command from the video controller, it drives the main motor in order to rotate the followings: photosensitive drum, de-
veloping cylinder, primary charging roller, transfer charging roller and pressure roller.
The primary charging roller allows the surface of the photosensitive drum to charge evenness negative. At the same time, the laser beam, modulated by the VIDEO
signals (VDO1, VDO2, /VDO1, /VDO2), is emitted onto the surface of photosensitive drum in order to format the latent image on the drum by the laser diode.
The latent image formed on the photosensitive drum is transferred into a visible image by the toner on the developing cylinder and the transfer charging roller trans-
fers it onto a print paper. Then the transferred toner onto a paper becomes a permanent image by heat and pressure in the fixing unit. After the surface of the pho-
tosensitive drum is cleaned by the cleaning blade, the drum potential is uniformed by the primary charging roller to get ready for the next print.
Fixing unit
Fixing film unit
Pressure roller
Video controller PCB

2.4.1.2 Print Process

LBP3370 / LBP3310
The principal process of the image formation is described in this paragraph.
The process can be broadly divided into 5 blocks with 7 steps. A toner image is formed on a print paper as it goes step by step in each block.
Paper path
Rotational direction of the drum

1. Electrostatic latent image formation block

Form an electrostatic latent image on the photosensitive drum.
Step 1: Primary charging (Charge the surface of the photosensitive drum uniformed negative potential)
Step 2: Laser beam exposure (Form an electrostatic latent image on the photosensitive drum)
2. Developing block
Make an electrostatic latent image on the photosensitive drum visible by applying the toner on.
Step 3: Development
3. Transfer block
Transfer a toner image on the photosensitive drum surface onto a print paper.
Step 4: Transfer (Transfer a toner on the photosensitive drum onto a print paper)
Step 5: Separation (Remove a paper from the photosensitive drum)
4. Fixing block
Fix a toner image on a print paper.
Step 6: Fixing
2-8
Primary charging roller
Cleaning blade
Photosensitive drum
Transfer charging roller
VIDEO signals (VDO, /VDO)
Print command

Electrostatic latent image formation block

Photosensitive drum cleaning block
Fixing block
Delivery
Laser/Scanner unit
Laser beam
Engine controller PCB
F-2-7
2. Laser beam exposure
1. Primary charging
7. Drum cleaning
5. Separation
6. Fixing
Transfer block
F-2-8
Cartridge
Developing cylinder
Developing block
3. Developing
Pick-up
4. Transfer
0018-3105