Lexmark C950 Service Manual - Page 342

5058-030 Service tips • If the surface of the charge roller is damaged (for example, if it has a nick or a pit), it will cause the charge to be uneven on the photoconductor. This will cause a repeating mark on the printed page. Check the service manual for the repeating marks table. • If the charge roller is severely damaged, the surface of the photoconductor will not be charged properly, and heavy amounts of toner will be deposited on the photoconductor. This will cause the printed page to be saturated with 100% of each color. The imaging basket will need to be replaced sooner. Step 2: Exposure The printhead LED generates a scan line of LED light. Image data received from the RIP card assembly modulates this scan line, turning it on and off according to image information that is received from the host computer and software. Through the use of a series of rotating and stationary mirrors within the printhead, the scan lines are applied on the negatively charged drum surface. Whenever the print controller sends a command to print a black pixel, the printhead LED switches on long enough to shine onto the drum at a single pixel point. That point is now discharged and slightly less negative than the surrounding negative charge. The less negative areas are considered positive. This discharge/no discharge process creates an invisible, electrostatic image on the surface of the drum. This image is called a latent image. LED Light DRUM Printhead Drum Surface Image Laser Beam Drum Surface Voltage Laser Beam Previous Next Go Back 0V Invisible Latent Image Discharge Level 3-54 Service Manual