Stock material or miscellaneous articles – Composite – Of silicon containing
Reexamination Certificate
1997-03-26
2002-11-12
Chapman, Mark A. (Department: 1756)
Stock material or miscellaneous articles
Composite
Of silicon containing
C428S448000, C428S450000, C492S056000, C399S333000
Reexamination Certificate
active
06479158
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a fuser member and method for fusing toner images in an electrostatographic reproducing apparatus. The present invention further relates to a method for preparation of such a fuser member. More specifically, the present invention relates to methods and apparatuses directed towards fusing toner images using a fuser member having an amino silane adhesive layer and an outer fluoroelastomer layer, and methods for the preparation of such fuser members.
In a typical electrostatographic reproducing apparatus, a light image of an original to be copied is recorded in the form of an electrostatic latent image upon a photosensitive member and the latent image is subsequently rendered visible by the application of electroscopic thermoplastic resin particles which are commonly referred to as toner. The visible toner image is then in a loose powdered form and can be easily disturbed or destroyed. The toner image is usually fixed or fused upon a support which may be the photosensitive member itself or other support sheet such as plain paper.
The use of thermal energy for fixing toner images onto a support member is well known. To fuse electroscopic toner material onto a support surface permanently by heat, it is usually necessary to elevate the temperature of the toner material to a point at which the constituents of the toner material coalesce and become tacky. This heating causes the toner to flow to some extent into the fibers or pores of the support member. Thereafter, as the toner material cools, solidification of the toner material causes the toner material to be firmly bonded to the support.
Typically, the thermoplastic resin particles are fused to the substrate by heating to a temperature of between about 90° C. to about 200° C. or higher depending upon the softening range of the particular resin used in the toner. It is undesirable, however, to increase the temperature of the substrate substantially higher than about 250° C. because of the tendency of the substrate to discolor or convert into fire at such elevated temperatures, particularly when the substrate is paper.
Several approaches to thermal fusing of electroscopic toner images have been described. These methods include providing the application of heat and pressure substantially concurrently by various means, a roll pair maintained in pressure contact, a belt member in pressure contact with a roll, a belt member in pressure contact with a heater, and the like. Heat may be applied by heating one or both of the rolls, plate members, or belt members. The fusing of the toner particles takes place when the proper combination of heat, pressure and contact time are provided. The balancing of these parameters to enable the fusing of the toner particles is well known in the art, and can be adjusted to suit particular machines or process conditions.
It is important in the fusing process that minimal or no offset of the toner particles from the support to the fuser member take place during normal operations. Toner particles offset onto the fuser member may subsequently transfer to other parts of the machine or onto the support in subsequent copying cycles, thus increasing the background or interfering with the material being copied there. The referred to “hot offset” occurs when the temperature of the toner is increased to a point where the toner particles liquefy and a splitting of the molten toner takes place during the fusing operation with a portion remaining on the fuser member. The hot offset temperature or degradation of the hot offset temperature is a measure of the release property of the fuser, and accordingly it is desired to provide a fusing surface which has a low surface energy to provide the necessary release. To ensure and maintain good release properties of the fuser, it has become customary to apply release agents to the fuser roll during the fusing operation. Typically, these materials are applied as thin films of, for example, silicone oils to prevent toner offset.
The process for the preparation of such fuser members is important in maintaining desired fuser life. Further, the composition of the layers, including the adhesive layer, are important in providing sufficient fuser life and prevention of toner offset. In particular, the bond between the fuser substrate and the outer surface must be sufficient in order to prevent the outer surface of the fuser member from debonding, resulting in fuser failure. The bond between the surface of the fuser member and the outer layer degrades as a function of time at the elevated temperatures involved in the fusing process which may exceed 400° F. Known adhesives such as the THIXON® epoxy adhesive (THIXON® is a trademark of Dayton Chemical Products Laboratories) degrade to the point where they no longer function as an adhesive and failure is experienced with wholescale debonding of the fusing layer from the fuser substrate, such that the fusing surface may be manually peeled from the substrate.
Known epoxy adhesives further require baking for solidification. This baking step is an additional timely and costly step in the manufacture of fuser members.
It is also important that the adhesive react sufficiently with the substrate and the outer layer so as to provide an even coat and to provide sufficient bonding of the outer layer. Known adhesives have been shown to form clumps and uneven coating of the fuser substrate.
Another important feature of the adhesive is that it should be compatible for use with processes for preparing fuser rolls. Known processes for providing surfaces of fuser members include two typical methods which are dipping of the substrate into a bath of coating solution or spraying the periphery of the substrate with the coating material. However, recently, a process has been developed which involves dripping material spirally over a horizontally rotating cylinder. Generally, in this new flow coating method, the coating is applied to the substrate by rotating the substrate in a horizontal position about a longitudinal axis and applying the coating from an applicator to the substrate in a spiral pattern in a controlled amount so that substantially all the coating that exits the applicator adheres to the substrate. For specific details of an embodiment of the flow coating method, attention is directed to commonly assigned, U.S. application Ser. No. 08/672,493 filed Jun. 26, 1996, entitled, “FLOW COATING PROCESS FOR MANUFACTURE OF POLYMERIC PRINTER ROLL AND BELT COMPONENTS,” the disclosure of which is hereby incorporated by reference in its entirety.
However, not all coatings and adhesives are compatible with the new flow coating method. Specifically, only materials which can be completely dissolved in a solvent can be flow coated. Further, it is desirable that the coating material have the ability to remain dissolved during the entire flow coating process which may take up to approximately 8 hours or longer, and remain dissolved during the manufacturing period which may take up to several days, for example about 1 to 5 days. Satisfactory results are not obtained with materials which tend to coagulate or crystallize within the time period required for flow coating. It is desirable to use a material capable of being flow coated for an increased amount of time to enable flow coating in a manufacturing and production environment. It is very costly to periodically shut down a manufacturing line and change the solution delivery system. If the adhesive does not have the desired properties, the assembly line may need to be shut down often, for example, every hour or every few hours in order to clean the delivery line of coagulated or crystallized material. Therefore, it is desirable to use a material which has good flow coating properties in order to allow for manufacturing to continue for a long period of time, for example several days, without occurring the above problems in the procedure.
It is also desirable that the adhesive be slow drying to avoid trapping solvent in the under layers which tends to cause
Finsterwalder Robert N.
Formicola, Jr. Anthony J.
Friel David M.
Kuntz Alan R.
Maxfield, Jr. David E.
Bade Annette L.
Chapman Mark A.
Xerox Corporation
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