WHY WE WILL USE A COROTRON ELECTRODE IN PHOTOCOPIER MACHINE
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Laser printer photo drums are made with a dopedsilicon diode sandwich structure with a hydrogen-doped silicon light-chargeable layer, a boron nitriderectifying (diode-causing) layer that minimizes current leakage, and a surface layer of silicon doped with oxygen or nitrogen; silicon nitride is a scuff-resistant material.
The steps of the process are described below as applied on a cylinder, as in a photocopier. Some variants are described within the text. Every step of the process has design variants. The physics of the xerographic process are discussed at length in a book.
Step 1. Charging
An electrostatic charge of −600 volts is uniformly distributed over the surface of the drum by a drum by a corona discharge from a corona unit (Corotron), with output limited by a control grid or screen. This effect can also be achieved with the use of a contact roller with a charge applied to it. Essentially, a corona discharge is generated by a narrow wire 1⁄4 to 1⁄2 inch (6.35 to 12.7 mm) apart from the photoconductor. A negative charge is placed on the wire, which will ionize the space between the wire and conductor, so electronswill be repelled and pushed away onto the conductor. The conductor is set on top of a conducting surface, kept at ground potential
The polarity is chosen to suit the positive or negative process. Positive process is used for producing black on white copies. Negative process is used for producing black on white from negative originals (mainly microfilm) and all digital printing and copying. This is to economize on the use of laser light by the "blackwriting" or "write to black" exposure method.
The steps of the process are described below as applied on a cylinder, as in a photocopier. Some variants are described within the text. Every step of the process has design variants. The physics of the xerographic process are discussed at length in a book.
Step 1. Charging
An electrostatic charge of −600 volts is uniformly distributed over the surface of the drum by a drum by a corona discharge from a corona unit (Corotron), with output limited by a control grid or screen. This effect can also be achieved with the use of a contact roller with a charge applied to it. Essentially, a corona discharge is generated by a narrow wire 1⁄4 to 1⁄2 inch (6.35 to 12.7 mm) apart from the photoconductor. A negative charge is placed on the wire, which will ionize the space between the wire and conductor, so electronswill be repelled and pushed away onto the conductor. The conductor is set on top of a conducting surface, kept at ground potential
The polarity is chosen to suit the positive or negative process. Positive process is used for producing black on white copies. Negative process is used for producing black on white from negative originals (mainly microfilm) and all digital printing and copying. This is to economize on the use of laser light by the "blackwriting" or "write to black" exposure method.
shahzebkhan:
SIR MY QUESTION IS WHY WE USE COROTRON NOT THE OTHER
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