DESCRIPTION: THE FIRST BOOK EVER WRITTEN FOR THE PUBLIC ON REPAIRING AND SERVICING PHOTOCOPY MACHINES. MANY PHOTOS MAKE IT VERY EASY TO UNDERSTAND. THE READER CAN SAVE HUNDREDS OF DOLLARS ANNUALLY WITH THE BOOK. REQUIRES NO SPECIAL TOOLS AND IS EASIER THAN YOU THINK.

ISBN: 1877767840

AUTHOR: RANDELL LYNN NYBORG
PRICE: $14.95

EXCERPT:
...it progresses through the machine, into the fixing assembly, which consists of two heated rollers which squeeze and heat the toner into the paper where it becomes fused. The paper then exits the machine with the copy image on its surface. That is an oversimplification of how copy machines work. We will now proceed to take a closer look and discuss service and repair techniques.
   As you know, to make a copy, an original is placed on the copyboard glass and the START button is pushed. A bright light can be seen under the copy board glass, immediately after the START button has been pushed. This is what is happening: the drum has had residual electrical charges neutralized. This is accomplished by a light (usually a bank of LEDs) adjacent to the drum. When they light, the drum surface conducts and surface charges are conducted to ground through the drum end bearings. The lights go out and the revolving drum is given an even electrical charge by means of high voltage corona wires. The copyboard lights come on and project the document image on to the drum as it revolves, usually via a system of mirrors and a lens. The light areas conduct and dissipate drum surface charges to ground, while the dark areas do not conduct and retain a charge. These dark areas are of course, the image areas of your copy original. These charged areas attract oppositely charged toner from the adjacent developing cylinder as both the drum and the developing cylinder are revolving. If you are getting ghost images from preceding copies, suspect that the erase lamp (LED bank) adjacent to the drum is malfunctioning in that it is not coming on or some of the LEDs aren't lighting.
   These lamps are easy to remove and replace. You should be able to see if it works by overriding the outside door switch and watching for it to light up just prior to making a copy. It should light the full length of the drum. On reduction copies, or any size of copy less than the maximum size sheet the copier can do, some of the LED's on the outer edge of the bank, light during the copy original exposure stage to prevent wide black margins on the outer edges of copies. If you are getting black edges on reduction copies, clean/replace lamp.
   The paper is fed into the machine from the paper tray. It is given a positive electrical charge via the transfer corona, and it passes under the drum and makes direct physical contact with the drum. Being of opposite charge, it attracts the toner from the drum onto the paper. The paper is also attracted to the drum. To prevent it from wrapping around the drum as it turns, a separation corona induces an opposite charge to the paper just after it picks off toner from the drum, reducing the attraction of the paper to the drum and allowing it to pass straight through the copy machine.

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