Magnetic toners containing cubical magnetite

摘要

This invention is generally directed to magnetic toners comprised of a styrene butadiene copolymer resin, and a cubically shaped magnetite material, which toners have a fusing latitude range of at least 30 degrees Fahrenheit up to a maximum temperature of 390 degrees Fahrenheit. Toners having melt fusing temperatures of from about 300 degrees Fahrenheit to about 375 degrees Fahrenheit are desirable. The preferred cubical magnetite used is Mapico Black, which is present in amounts of from about 40 percent to about 70 percent. The toners of the present invention are useful for example in magnetic imaging systems, especially systems employing heat pressure fusing and high speed fusing systems.