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Laser Printer Operation Quiz

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Laser Printer Operation Quiz

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[edit section] Laser Printer Operataion Quiz

Label each of the following steps of a laser printers operation. Image: PrinterQuiz.GIF

Transferring In this step, the toner attached to the latent image is placed onto the paper. The secondary corona places a positive charge on the paper. Since the drum was charged negatively, it attracts the negative toner image from the drum to the paper. The image is now on the paper and is held in place by the positive charge.

Fusing The toner particles on the paper are only there because of the charge that is present. They are kept in place permanently by this process. In this process, the printing paper is rolled between a heated roller and a pressure roller. As the paper rolls, the top roller is heated to about 350 degrees, which melts the loose toner powder to the fibers in the paper. This operation is called fixing by some manufacturers. After this operation is complete, the paper is moved to the output tray as a printed page.

Conditioning This step involves removing the old latent image from the drum and clearing the drum for a new latent image. Placing a special wire, grid, or roller that is charged to about –600 volts DC uniformly across the surface of the drum accomplishes this. This charged wire or grid is referred to as the primary corona. Some printers provide this charge by using a special roller. The charge impressed upon the surface of the drum is -600 to -1000 volts DC.

Writing This process involves scanning the photosensitive drum with the laser beam. Every portion of the drum that is exposed to the light has the surface charge reduced to about -100 volts DC. This electrical charge has a lower negative charge than the remainder of the drum. As the drum turns, an invisible latent image is created on the drum. Figure illustrates the various voltage transitions involved with creating a printed page in the laser printing process.

Cleaning When an image has been deposited on the paper and the drum has separated from the paper, any remaining toner must be removed from the drum. One method uses a blade to scrape all excess toner from the drum. Other printers use an AC voltage on a wire that removes the charge from the drum surface and allows the excess toner to fall away from the drum. The excess toner is stored in a used toner container that may be emptied and/or discarded.

Developing This is the step where the toner is applied to the latent image. Inside the toner unit are particles made up of magnetic materials. These magnetic particles are coated with a plastic-like material. A triboelectric charge on the particles causes it to attract toner. The toner as, a result, is charged to around -200 volts DC. This causes it to be attracted to the more positive or -100 volts DC areas of the photosensitive drum. However, it is repelled by the more negative or -600 volts DC areas. Typically, a cylinder within the toner unit releases toner so it can fall against a control blade as the rollers travel. Also known as the restricting blade, the control blade keeps toner from pouring onto the drum. Instead, it holds the toner at a microscopic distance from the drum. The toner then leaps from the control blade to the drum where it is attracted by the more positively charged latent image.

[edit section] See Also

Laser Printer Steps : Answer To This Quiz

Trick For Remembering Laser Printing Process on the exam

[edit section] Acknowledgements

Created by Eric

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