Grease is the Word

But which grease is recommended for the multiple requirements in a laser printer cartridge?
Some claim that all greases are basically the same, but that isn’t the case. Greases are developed for many different purposes, and the wrong grease can cause multiple problems in laser printer cartridges.

Grease is required in many areas of the laser printer cartridge, including the PCR saddle (one side electrically conductive, the other insulative), OPC hub bearing, magnetic roller contact fingers or contact spring, developer roller shaft, end cap electrical contacts and even for general use on mating gears.

Grease is categorized by the National Lubricating Grease Institute (NLGI) into nine viscosity categories. These range from 000 (very thin) to 6 (very thick). In general, greases have a base material that is either organic or synthetic, a thickener type (usually lithium soap, lithium complex or polyurea), and will often have additives to give the proper operating temperature range, oxidation stability, film strength, and bleed resistance characteristics.

It is important to use the proper grease to prevent noise, lubricant migration or dissipation that can result in higher torque for revolving components, which could eventually damage the printer.

A good general-use choice for all non-conductive applications would be a high temperature, silicone-based grease with a lithium thickener of grade #1 or #2, containing 0 grams per liter of Volatile Organic Compounds (VOCs).

Be careful not to use too much though, and be sure to control the application method to keep it from getting onto work surfaces or other cartridge parts.

A proven brand is the Dow Corning® Molykote® 44 High Temp. Grease, which is available from most national industrial supply distributors (Grainger’s Part # 6Y767).

Another type of grease is required to improve electrical conductivity for areas between sliding or revolving surfaces that may be slightly irregular, pitted or unevenly worn.

The wrong grease can result in poor conduction, causing print defects and, in some cases, even the degradation of components like the OPC and PCR.

There are two basic types of conductive greases. One has carbon as the conductor, while the other uses minute metal particles such as copper, nickel or silver added to the lubricant. These metal conductive lubricants can be very expensive and their conductive characteristics (down to 0.01 ohms / cm) are not required here.

A good carbon-based lubricant containing oxide inhibitors that have a resistivity in the neighborhood of 117 ohms / cm will work very well for the electrical conduction requirements in laser printer cartridges.

One such electrically-conductive grease distributed by Future Graphics Imaging Corporation carries the product name LIGHTNINGLUBE.

Proper choice of grease with prudent application will alleviate many potential problems.