Electrophotography – Image formation – Fixing
Reexamination Certificate
1999-12-16
2001-04-24
Chen, Sophia S. (Department: 2852)
Electrophotography
Image formation
Fixing
C399S071000
Reexamination Certificate
active
06223016
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to cleaning systems for electrostatographic printing machines, and more particularly this invention relates to a cleaning station engaging the fusing member of a printing machine.
BACKGROUND TO THE INVENTION
Electrostatic printers are known in which a toner image is fused or fixed to a substrate to form a final document. The fusing can occur after transfer of the toner image to the substrate, or transfer and fusing simultaneously occur in a transfuse process. In either arrangement the substrate is fed into a fusing nip where a combination of fusing members, such as fusing or transfuse belts or rollers, apply heat and pressure to the toner image and substrate to fix or fuse the toner image to the substrate. During the fusing process, toner particles from the toner image and debris from the substrate can adhere to the fusing member. These toner particles and other debris, contaminants, can transfer from the fusing member to subsequent documents resulting in print defects. In addition, build up of toner particles on the fusing member can degrade the quality of fusing of the toner image on subsequent documents. The build up of toner particles can also decrease the operational life of the fusing member.
Therefore it is preferred to clean the fusing members to remove toner particles and other particulate debris, such as dirt and fiber, that effect final print quality.
One prior cleaner employed a cleaning roller engaging the surface of a fuser roll to remove toner particles. Toner particles preferentially adhered to the cleaner roller. However, as excess toner particles accumulate on the cleaner roller, the toner layer on the surface of the cleaner roller can become uneven, resulting in uneven cleaning of the fusing member. The toner layer on the cleaner roller can become excessively thick, requiring maintenance to remove the excess toner of the toner layer.
In one alternative assembly, the cleaner roller is formed of a hollow cylinder and apertures are provided in the cylinder to permit excess toner to be driven inward through the openings. Excess toner therefore is collected on the inside of the cylinder, extending the period between servicing or the life of the cleaner roller. However, the openings can result in gaps in the cleaning surface of the roller, requiring multiple cycles to the fusing member to completely clean the surface of the fusing member by the cleaner roller. Therefore toner particles on the fusing member can continue to disrupt fusing, or be transferred to subsequent documents, before their removal.
SUMMARY OF THE INVENTION
Briefly stated, a cleaner station in accordance with the invention has a carousel or turret supporting a plurality of cleaner roller assemblies cleaningly engageable to a fusing member. The carousel is indexed to in turn position each cleaner roller assembly in contact with the fusing member for cleaning. Each cleaner roller assembly cleans the surface of the fusing member for a preestablished operational period, for example a preestablished number of pages. At termination of the preestablished operational period, the used cleaner roller assembly is moved out of engagement with the fusing member and a second cleaner roller assembly is brought into cleaning engagement with the fusing member. In a first embodiment, each cleaner roller assembly is formed of a continuous surface or solid surface cleaner roller rotatably mounted to the carousel. The cleaner roller in contact with the fusing member is heated within the tacky range of the toner employed in the printing apparatus. Toner particles and other particulates such as dirt and fiber adhere to the tacky toner layer formed on the cleaner roller and are thereby cleaner from the fusing member. The use of a solid surface cleaning roller allows for effective single pass cleaning of the fusing member.
In a further embodiment of a cleaning station in accordance with the invention, each cleaner roll assembly has a perforated cleaner roller. Each cleaner roller defines an internal reservoir. The cleaner roller in contact with the fusing member is heated within the tacky range of the toner employed in the printing apparatus. Toner particles and other particulates such as dirt and fiber adhere to the tacky toner layer and are thereby cleaned from the fusing member. Excess toner collected on the cleaner roller is forced into the reservoir to thereby extend the operational life of the perforated cleaner roller.
In a still further embodiment each cleaning assembly has a pair of rotatably mounted cleaning rollers. The first cleaning roller in the process direction of the fusing member is a perforated cleaner roller. The second cleaner roller has a solid surface and is positioned down stream in the process direction from the first cleaning roller. The cleaner roller in contact with the fusing member is heated within the tacky range of the toner employed in the printing apparatus. Toner particles and other particulates such as dirt and fiber adhere to the tacky toner layer and are thereby cleaned from the fusing member. The use of at least one solid surface cleaner roller allows for effective single pass cleaning of the fusing member.
The cleaner station in accordance with the invention is described in combination with a fusing member formed of a transfuse belt. The cleaner station is additionally applicable with other fusing members, such as transfuse rollers, fuser rollers and fuser belts. Single pass cleaning is particularly important for transfuse systems where toner images are cyclically transferred to and from the transfuse member, increasing the potential of stray toner particles adhering to the fusing member.
REFERENCES:
patent: 5253025 (1993-10-01), Mitsuya et al.
patent: 5519476 (1996-05-01), Dalal et al.
patent: 5678134 (1997-10-01), Miki et al.
patent: 5835837 (1998-11-01), Saitoh et al.
patent: 5890048 (1999-03-01), Hirota
Berkes John S.
Fletcher Gerald M.
Jia Nancy Y.
Chen Sophia S.
Cunningham Reid K.
Kepres Kevin R.
Xerox Corporation
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