Patent Application
20090317156
1. Field of the Invention
The present invention relates to image forming apparatus and their fuser members and, more particularly, to methods of forming a fuser member to include a selectively polished fuser member surface.
2. Background of the Invention
In electrostatographic fixing systems, fuser members are often coated with a non-adhesive coating including fluoroelastomer polymer to overcome toner offsetting and staining, i.e. the adhesion of the heat softened toner particles onto the surface of the fuser member. In addition, these fluoroelastomer polymers can provide a release coating to a surface of the fuser members, such that a paper stripping is more easily accomplished. In other cases, the fluoroelastomer coating is of a type to provide both high gloss and good release of fused toner images. It is well known that the performance of the fuser members is dependent on the surface uniformity of the fuser member and substantial investment is made to provide a consistent and reliable fuser member.
After a fuser member has been installed in, for example an electrostatographic machine, the combination of fuser oil or fuser release agent, and/or toner, can form a sticky gel that adheres to the fuser member surface. In turn, this coating reduces the fuser member performance and longevity. Likewise, the repeated application and release of a sheet or the like on a surface of the fuser member can cause variations in surface uniformity of the fuser member, primarily due to toner and/or oil on the surface of the fuser member. Even further, the gloss of the fuser member can eventually vary over a surface of the fuser member as a result of repeated contact and stripping of paper from the fuser member. It is a discovery of the invention that the areas of greatest wear on the fuser surface correspond to edges of a sheet applied and released thereon. For example a sheet width of 11 inches centered on a fuser member will wear away the surface of the fuser member faster at edges of the paper. Similarly, if the sheet is edge aligned on the fuser member, then the edge wear (assuming the same size sheet) can form 11 inches from the alignment edge. This phenomenon can be referred to as sheet edge wear.
While a certain amount of wear can be expected with the repeated use of the same sized paper, the wear can eventually cause image defects on the print product. For example, fluoroelastomer (e.g. Viton™) coated fuser members, and especially those used in color fusing, have a failure mode whereby the prints have noticeable gloss variation as the fuser wears. While even the worn areas of the fuser member often yield absolute gloss that is well within normal specifications, a variation of as little as 2 gloss units between sheet edge wear regions and adjacent less worn regions can be cause for failure. This phenomenon can be referred to as Edge Delta Gloss (EDG) print defect.
Currently, in order to maintain uniformity of the fuser member, and more particularly, correct the EDG print defect, it is known to move the paper edge or accessories relative to the fuser member surface. Continuous adjustment of paper feed and/or hardware equipment eventually becomes ineffective.
It is further known that forming a fuser member often includes polishing of the surface. Polishing can help to make the surface uniform in appearance and can remove some potential surface defects. In addition, polishing the surface of a fluoroelastomer can improve release and/or stripping performance of the fuser member. Finally, polishing can provide a resulting surface higher in Fluorine, thereby improving offset and stripping performance. However, a problem has been found herein that polishing the fuser member surface causes a significant reduction in fuser life.
Typically, color machines have a significant quantity of failures associated with gloss variation in the prints at the paper edge, where the roll surface usually becomes dull compared to the high gloss of the rest of the roll. Particularly with color systems, the gloss variation may occur at a low number of prints while there is still plenty of life left in the coating release properties as well as the mechanical durability of the under layers which are typically silicone or fluorocarbon. According to the invention herein, the problem with polishing the fuser member surface is that it has been found to accelerate the EDG failure mode, as measured in stress testing when compared to the typical unsanded surface. An example of an iGen3 machine run to 2500 prints with 210 gsm stock provides support for this discovery. The attached graph of
Accordingly, polishing a surface of the fuser member provides advantages that would be lost if the surface were not polished. Previously, however, an entire surface of the fuser member has been polished, which directly leads to the EDG defects described.
Accordingly, there is a need to overcome these and other problems of prior art to provide a method for selectively polishing a fuser member surface.
In accordance with various embodiments, a fuser member is provided.
The fuser member can include a substrate having a first edge and a second edge; and a continuous fluoroelastomer layer disposed over an entire surface of the substrate, the continuous fluoroelastomer layer comprising a selectively polished region.
According to various embodiments, there is a method of making a fuser member.
The method can include selectively polishing those portions of the surface not subject to a great probability of high natural wear.
According to another embodiment, an image forming apparatus includes fuser member having a selectively polished surface.
Additional advantages of the embodiments will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The advantages will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.
Reference will now be made in detail to the present embodiments, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein are to be understood to encompass any and all sub-ranges subsumed therein. For example, a range of “less than 10” can include any and all sub-ranges between (and including) the minimum value of zero and the maximum value of 10, that is, any and all sub-ranges having a minimum value of equal to or greater than zero and a maximum value of equal to or less than 10, e.g., 1 to 5. In certain cases, the numerical values as stated for the parameter can take on negative values. In this case, the example value of range stated as “less that 10” can assume negative values, e.g. −1, −2, −3, −10, −20, −30, etc.
As used herein, the term “fuser member” is used interchangeably with the terms including fuser rolls, fuser belts, transfix members, pressure members and fuser films.
As used herein, “gloss” is measured in gloss units, which uses the angle of measurement and the gloss value at 75 degrees per the American Society for Testing and Materials (ASTM) D523 standard for the general evaluation of gloss.
In some embodiments, the sheet edge wear region 292 can include two edges, as depicted in
It will be appreciated that an alignment (registration) edge of a fuser member is typically not polished in the exemplary embodiments. However, the non-registration edge can vary in location according to factors such as sheet size, hardware and setup, and the non-registration edge therefore can be selectively polished or not according to wear parameters thereof.
In various embodiments, and as depicted in each of
Any suitable material that has satisfactory heat transfer and strength characteristics can be used as the substrate 280 for the fuser member 200. The fuser member 200 can be a roll, belt, flat surface or other suitable shape used in the fixing or conditioning of thermoplastic or thermoset toner or ink images to a suitable media. The fuser member 200 can be a pressure member or a release agent donor member or a transfix member, preferably in the form of a cylindrical roll, belt, or film. Typically, the roll fuser member can be made of a hollow cylindrical metal core, such as copper, aluminum, steel, materials chosen to maintain rigidity, structural integrity, as well as being capable of having a fluoroelastomer coated thereon and adhered firmly thereto.
In various embodiments, the continuous fluoroelastomer layer 290 can include fluoroelastomer polymer selected from the group consisting of copolymers of vinylidene fluoride, hexafluoropropylene, and tetrafluorothylene; and terpolymers of vinylidene fluoride, hexafluoropropylene, and tetrafluorothylene. Other suitable polymers are described in detail in the U.S. Pat. No. 5,945,223, the disclosure of which is incorporated herein in its entirety.
In various embodiments, the continuous fluoroelastomer layer 290 can include a thickness from about 5 μm to about 250 μm when formed over the substrate 280. However, one of ordinary skill in the art would know that subsequent post coating operations, such as, for example, grinding and/or polishing can vary the initial thickness of the layer.
According to various embodiments,
According to various embodiments, an image forming apparatus 400 is shown in
The exemplary fuser member 410 shown in the apparatus 400 is a fuser roll. However, the process described above can be used to provide fuser belts or films. The fuser belts or films can be preferably mounted on a cylindrical mandrill and processed in a manner process similar to that heretofore described, with the outer surface of the belt or film being selectively polished.
While the invention has been illustrated respect to one or more implementations, alterations and/or modifications can be made to the illustrated examples without departing from the spirit and scope of the appended claims. In addition, while a particular feature of the invention may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular function. Furthermore, to the extent that the terms “including”, “includes”, “having”, “has”, “with”, or variants thereof are used in either the detailed description and the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.” As used herein, the phrase “one or more of”, for example, A, B, and C means any of the following: either A, B, or C alone; or combinations of two, such as A and B, B and C, and A and C; or combinations of three A, B and C.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
