Copiadoras

CARTRIDGE PRINTING THEORY
By Mike Josiah

Over the years we have compiled quite a bit of information on cartridge printing theory from a number of sources; OEM service manuals, patents, and OEM training manuals to name a few. Much of this has been included in various cartridge articles, but much was also left out, or never written about at all. While knowing cartridge theory is not reallynecessary to remanufacture a cartridge, it is really helpful when trying to troubleshoot a problem. The ability to troubleshoot a cartridge that is new to your production line fast and correctly is, as the saying goes, “priceless.” We have broken down the various cartridge types into six separate categories: CATEGORY Magnetic Toner Non-Magnetic Toner Non-Magnetic Single-Pass Color Toner Non-MagneticCarousel Color Toner Brother HL-1240 Toner Dual Component systems ENGINE Monochrome HP LaserJet Monochrome Lexmark & Samsung HP Color LaserJet 4600 HP Color LaserJet 1500/2500 Brother HL-1240 Analog Sharp Copiers

Some of the sections are specific to a single cartridge, and some are very broad. In either case, the information will hopefully help the next time you have a problem you may not haveseen before. While technology is improving cartridge components and their printers at a very fast rate, the basis that they work on has changed very little. The biggest change I have seen was when HP and Canon moved from Corona Wires to Charge rollers. Other than that, toner particle size has gotten smaller, melt points are lower, the charges needed are less, and of course chips have been added butthe cartridges all basically work the same as they did when their basic style was first released. While it is impossible to see what will happen in the future, from the patents I have seen, this trend will continue for a while longer.

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TECHNICAL GUIDES • CARTRIDGE PRINTING THEORY

MAGNETIC TONER • MONOCHROME HP LASERJET The Magnetic Toner cartridge printing process is best explained as a series ofsteps or stages. In the First Stage, the Primary Charge roller (PCR) places a uniform negative DC Bias voltage on the OPC drum surface. The amount of the negative DC Bias placed on the drum is controlled by the printer’s intensity setting. This process is called Conditioning. In the Second Stage (also called the Imaging Section), the laser beam is fired onto a rotating mirror (called the scanner). Asthe mirror rotates, the beam reflects into a set of focusing lenses. The beam then strikes the OPC’s surface, leaving a latent electrostatic image on the drum. In most cartridges, the OPC drum makes approximately three revolutions for each 11-inch printed page. The Third Stage (Developing Stage) is where the toner image is developed on the drum by the developing section, (or supply chamber), whichcontains the toner particles. The toner is held to the magnetic roller sleeve by the stationary magnet inside the sleeve, and a DC bias voltage supplied by the high-voltage power supply. This DC bias voltage is controlled by the printer’s intensity setting, and causes either more or less toner to be attracted to the drum. This in turn will either increase or decrease the print density. Both thePrimary Charge roller and magnetic roller DC Bias voltages are controlled by the printer’s intensity setting. The amount of toner on the magnetic roller sleeve is controlled by the rubber Doctor Blade, which uses pressure to keep the amount of toner on the magnetic roller sleeve constant. This blade also causes a static charge to build up on the toner, which helps keep the coating of toner even,...