Minggu, 02 Maret 2014

Image formation system and Image formation process hp laserjet p 4010 and p 4015 series

Image-formation system
The image-formation system is the central hub of the product. It forms the toner image on the media. The following are the main components of the image-formation system:
• Cartridge
• Transfer roller
• Fuser

The DC controller controls the laser/scanner unit and high-voltage power supply to form an image on the media according to the VIDEO signals.
Image-formation process
The image formation system is the central hub of the product. It also forms the toner image on the media. Figure 5-14 Image-formation system

The image-formation process contains eight steps divided among five functional blocks:
• Block 1: Latent image formation
Step 1: Primary charging
Step 2: Laser-beam exposure
• Block 2: Developing
Step 3: Developing
• Block 3: Transfer
Step 4: Transfer
Step 5: Separation
• Block 4: Fusing
Step 6: Fusing
• Block 5: Drum cleaning
Step 7: Drum cleaning
Step 8: Drum charge elimination

Figure  Image-formation process

Block 1: Latent image formation
During the two steps that comprise this block, an invisible latent image is formed on the photosensitive drum.
Step 1: Primary charging
To prepare for latent image formation, the surface of the photosensitive drum is charged with a uniform negative potential. The product charges the photosensitive drum surface directly from the primary

charging roller. The DC bias and AC bias are applied to the primary charging roller to maintain a constant charge on the drum surface.

Figure  Primary charging
Primary charging roller

Step 2: Laser-beam exposure
The laser beam scans the photosensitive drum to neutralize the negative charge on portions of the drum surface. An electrostatic latent image forms where the negative charge was neutralized.
Figure 5-17 Laser-beam exposure
Laser beam

Block 2: Developing
Toner adheres to the electrostatic latent image on the photosensitive drum.

Step 3: Developing
Toner acquires a negative charge from the friction that occurs when the developing cylinder rotates against the developing blade. The negatively charged toner is attracted to the latent image on the

photosensitive drum surface because the drum surface has a higher potential. The AC bias that is superimposed with the developing negative DC bias is applied to the developing cylinder.

Figure  Developing

The positive DC bias is applied to the transfer roller to charge the media positive. The positively charged media attracts the negatively charged toner from the photosensitive drum surface.

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