Patent Application
20100065675
This invention relates to a mandrel useful in the production of coated belts.
While the present mandrel invention can be used in any suitable coated belt production system, it will be described herein for clarity as used in the production of belts useful in electrostatic marking systems.
By way of background, generally, in a commercial electrostatographic reproduction apparatus (such as copiers/duplicators, printers or the like), a latent image charge pattern is formed on a uniformly charged photoconductive or dielectric member. Pigmented marking particles (toner) are attracted to the latent image charge pattern to develop such image on the dielectric member. A receiver member, such as paper, is then brought into contact with the dielectric member and an electric field applied to transfer the marking particle developed image to the receiver member from the dielectric member. After transfer, the receiver member bearing the transferred image is transported away from the dielectric member and the image is fixed or fused to the receiver member by heat and/or pressure to form a permanent reproduction thereon. In a typical fusing process where the toner is fused to the paper or receiving media, two rolls or belts are used through which the paper travels during the toner fusing. One roll or belt, usually the harder roll or belt, is a fuser member, the second is the pressure member or the softer roll or belt. “Fuser or pressure member as used throughout this disclosure includes both rolls and belts.
Typical pressure rolls or belts (“Softer Member”) that are used in a fusing system have an elastomeric coating like silicone rubber which may or may not have a thin layer of another material over the surface of the member. A functional nip is formed when the softer member is pressed into the fuser member (“Harder Member”). The fuser member generally comprises a metal core with a hard Teflon (™ of DuPont) coating or thin elastomer.
The pressure or softer members are typically constructed of a cylindrical steel core or rod having positioned over it an elastomer or rubber material cylindrical coating. In any system when a hard (fuser member) is pressed against and contacts a softer member, nips are formed throughout the length of the pressure member in contact with the fuser member. These pressure zones ultimately cause the softer material to contact the support plates and create wear, shortening roll life and causing debris in the system. Also, once excessive wear takes place and an uneven nip is formed because of uneven coating, improper fusing of the toner can result causing imperfect copies on the paper or receiving member. In addition, because of this wear problem caused by non-precise surface coating, frequent changes requiring new softer members are required. Generally, the elastomeric members have typically been manufactured from a single elastomeric material, such as silicon rubber, of a uniform hardness as determined by a durometer. From both a cost standpoint and performance standpoint, any improvement in the softer and harder member, construction that would extend roll life and improve performance at the fuser station would be very desirable. Also, eliminating an uneven nip and material deterioration of the pressure member would extend pressure and fuser member life and substantially improve fusing performance. An improved method for precisely coating fusing members will substantially eliminate or lessen deterioration of these fusing members.
Prior to the present invention, this was no efficient and inexpensive method to securely hold onto a large (such as a) 300 mm diameter belt during the surface coating steps. An efficient system is needed to allow a user to apply precision coatings and execute precise process steps in making fusing members or other coated belts.
The expandable mandrel of this invention allows a large belt to be held precisely on the centers of lathes and other equipment. One object of this invention is to avoid the costs of purchasing a prior art expensive alternative that generally consisted of an air-filled bladder chuck.
This invention describes a mandrel developed and used to fabricate in one embodiment fuser belts or other non-xerographic related coated members. This mandrel was specially developed as nothing is now commercially available that meets the rigid requirements for precise belt manufacturing. It consists in one embodiment of two sets of end caps, two Viton “O” rings, (VITON is a ™ of DuPont) an aluminum core, a piece of thin tubular stainless steel sheeting and about a 1 mm thick circular silicone belt. The stainless steel sheet is rolled over itself in a circular shape smaller than that of the silicone belt and is placed inside the silicone belt. The silicone belt eliminates the seam where the steel sheet overlaps itself and acts to hold the polyimide belt in place. In making a fuser belt, a polyimide belt that will be the substrate for the manufactured belt is then slipped over the silicone belt. In non-xerographic use, any suitable substrate that is to be coated may be used. The end caps and core are placed inside the steel sheet and the end caps are tightened axially. The end caps house the O-rings in a nest slightly smaller than the width of the O-ring. As the end caps are drawn together with screws, the O-rings expand outwards, pushing against the steel sheet and silicone belt, securing the polyimide belt onto the assembly with a consistent force in a nearly perfect circular shape. Finally, the assembly is mounted in a lathe and fuser belts are manufactured by flow coating a material, like silicone, onto a polyimide belt substrate, followed by other layers of Viton or Teflon (both trademarks of DuPont) on top of the silicone. This invention was implemented and shown to work well in producing 302 mm diameter fuser belts. Other size mandrels could be made for different diameter belts. This mandrel was specially developed because nothing is commercially available that meets the requirements including notably the need to withstand high belt curing temperature. Another key advantage of the present mandrel is creating an essentially perfect circular shape suitable substrate for flow coating. This is an efficient configuration that is a key enabler for seamless belt manufacture for fusing or ITB applications and could have useful potential to manufacturing equipment suppliers or for various other types of belts including in other industries not related to xerography.
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The channel or groove 6 may be placed in either or both plates 3 and 5 so that an O-ring 7 may be placed therebetween. The important feature is that the O-ring be placed between plates 3 and 5 so that upon tightening these plates, the deformable O-ring will bulge outwardly as shown in
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In summary, this invention provides a mandrel useful in the manufacture of coated belts, the mandrel comprising a center tubular core having plates on each of its end portions, a first round metal plate secured to said tubular core. The first or second round plates have a groove channel concentrically machined adjacent the inside face of its inner perimeter. A deformable O-ring is nested into the grooved channel and sandwiched between the first and second round plates. There are bolts positioned in the first round plate on its outer portion and adapted to be tightened evenly to squeeze the first and second round plates together thereby forcing a portion of said O-ring outwardly beyond the outer perimeters of the first and second round plates. The O-ring is configured thereby to substantially equally space a belt to be positioned on and over the O-rings and mandrel prior to precision coating said belt.
The bolts are equally spaced around an outside portion of the first round plate. The O-ring comprises a silicone O-ring. The first round metal plate is preferably constructed of aluminum. The first and second round plates are coextensive and have equal configured center openings adapted to fit around the center tubular core.
Embodiments of this invention provide a device useful in a process of applying a uniform coating on a belt structure. The device comprises a mandrel, a metallic tubular sheet enabled to fit around the mandrel, a flexible belt enabled to fit around the metallic tubular sheet, and a coatable belt structure enabled to fit around the flexible belt and providing a substrate to be coated. The mandrel comprises a center tubular core having attached on each of its end portions a first and second round plate. At least one of the round plates has a groove channel machined on its inner face abutting the other plate, and an O-ring fitted into the channel and enabled to be squeezed and deformed outwardly upon tightening together of the first and second round plates. The mandrel has at least four bolts equally spaced around an outside portion of the first round plate. The O-ring is elastomeric and deformable. The first round metal plate is preferably constructed of aluminum. The first and second round plates are coextensive and have equally configured center openings adapted to be connected to and fit around the center tubular core.
Also provided by embodiments of this invention is a process for the production of a fuser belt useful in a xerographic marking system. This process comprises providing a mandrel, providing a metallic tubular sheet enabled to fit around said mandrel, providing a flexible belt enabled to fit around said metallic tubular sheet, and providing a belt structure enabled to fit around said flexible belt thereby providing a substrate to be coated to form a fuser belt. The mandrel comprises a center tubular core having on each of its end portions a first round metal plate attached to the tubular core, a second round plate secured to the tubular core. The first and/or second round plate has a groove channel concentrically machined adjacent the inside face of its outer perimeter. A deformable O-ring is nested into the grooved channel and is sandwiched between the first and second round plates. There are bolts positioned in the first round plate and adapted to be tightened evenly to squeeze the first and second round plates together thereby forcing a portion of said O-ring outwardly beyond the perimeters of the first and second round plates. This provides substantially equally spacing a coatable belt to be positioned on the mandrel prior to precision coating the belt. The bolts are equally spaced around an outside portion of the first round plate. The O-ring is a silicone O-ring. The first round metal plate is constructed of aluminum, the first and second round plates are coextensive and have center openings adapted to fit around the center tubular core. The metallic tubular sheet is a stainless steel sheet, the flexible belt is a seamless silicone belt, and the coatable belt structure is a polyimide belt.
It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
