It is for a fact that good laser prints follows a fully operational fuser assembly that is in good condition as well. Well, that is if the conventional fuser unit can deliver heat ranges from between 180 to 210 degrees Fahrenheit, a temperature at which toner can successfully melt and bond to paper fibers. But what substances make up the fuser that allows it to withstand immense heat while being durable enough to contain the abrasive properties of paper or media?
Two materials or substances have been identified, the silicone and fluoroelastomers. Both materials exhibit the physical properties necessary for fuser rollers to perform seamlessly over long periods of printing.
The polymer coating outfitted with fusers include certain grades of silicone rubber that resists high heat. Said coating must work in conjunction with elastomers to provide satisfactory release properties. Otherwise, toner particles will stick to the fuser surface without the release agent and ultimately result in poor quality prints.
This is however easier said than done because the mentioned substances are really expensive. Silicone and other additives cost at least $100 per kilogram. But the most daunting task of all is the application of these substances into a circular fuser housing that could really hike up the cost of the fuser assembly.
Earlier technology employed in the application of coating to the fuser's surface involves spraying the polymer directly into the fuser surface by molding it into the fuser. Recently, the thin coat flow coating technology is gaining ground. Said technology relatively uses minimal raw materials; is almost solvent free and could be used to coat fusers of varying sizes. The previous process of electro-statically spraying polymer into the fuser housing is not environment friendly as it involves at least 30% solvent mixed with 70% polymers. Moreover, the entire process is not only difficult to follow through and requiring expensive equipment but is also labor intensive and accrues a lot of waste materials borne of over spraying.
Molding polymers on the other hand is more simple as it only requires a cardboard molder set in place where polymer is injected into the formed cavities. It is then cured typically in a press for about 5 minutes at 1,500 degrees Celsius or one and a half hours at 65 degrees Celsius. Thin coat flow coating promotes even polymer thickness and could really be thin to as much as fractions of a millimeter (0.25 mm). This technology has been used extensively in the polyurethane industry to provide thick coatings to spinning surfaces and is proven to be cost effective. Indeed, the technical innovations introduced in the production of conventional fusers has produced eco-friendly and cost responsive laser printers.
Knowing the Fuser Assembly’s physical and material properties could give users the edge in understanding the intricate role the fuser play in the electro-photographic (EP) printing process.
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