Lexmark C950 Service Manual - Page 340

5058-030 Printer theory of operations Print engine theory Four toner cartridges (cyan, yellow, magenta, and black) are used to create text and images on media. Each of the colors has a photoconductor drum and an image transfer unit (ITU). To obtain a print output, each drum will undergo the following processes: 1. Charge 2. Exposure 3. Development 4. 1st transfer 5. Cleaning (Drum/Charge roll) 6. 2nd Transfer 7. Electric Discharge 8. Cleaning (Transfer belt/2nd transfer roll) 9. Fusing Printing process flow DRUM (Y) charge exposure Cleaning (Drum/Charge roll) development DRUM (M) charge exposure Cleaning (Drum/Charge roll) development DRUM C charge exposure Cleaning (Drum/Charge roll) development DRUM (K) charge exposure Cleaning (Drum/Charge roll) development Belt Cleaning (Transfer belt/2nd transfer roll 1st transfer 1st transfer 1st transfer 2nd transfer 1st transfer Paper Electric discharge Fusing In summary, the printer's controller board receives print data and the command to print. The controller board then initiates the print process. The controller board is the command center for the EP process and coordinates the various motors and signals. The high-voltage power supply sends a charge to various components in the EP process. The printhead LED arrays fire on the photoconductors and alter the surface charge relative to the planed image for each photoconductor. Each photoconductor rotates past its respective developer roll, and toner is developed on the surface of each photoconductor. The four separate color images are then transferred to the transfer belt as it passes under the photoconductors. After the image is transferred to the transfer belt, the photoconductors are cleaned and recharged. The transfer belt carries the four-colored image towards the transfer roll. Media is picked up from the tray and carried to the transfer roll where the image is then transferred from the transfer belt to the media. The timing of the paper pick is determined by the speed of the transfer belt. The media is carried to the fuser belt and roller where heat and pressure are applied to the page to permanently bond the toner to the page. The fuser rollers push the media into the output bin. The transfer unit is cleaned and the process begins again for the next page. Previous Next Go Back 3-52 Service Manual