Stock material or miscellaneous articles – Composite – Of silicon containing
Reexamination Certificate
1999-06-16
2001-11-13
Dixon, Merrick (Department: 1774)
Stock material or miscellaneous articles
Composite
Of silicon containing
C428S332000, C428S461000, C428S469000
Reexamination Certificate
active
06316113
ABSTRACT:
The present invention relates to a method and apparatus for a printing system. More specifically, the invention relates to printer rolls and belts for printing systems.
The features of the present invention are useful in the printing arts and more particularly in electrophotographic printing. In the well-known process of electrophotographic printing, a charge retentive surface, typically known as a photoreceptor, is electrostatically charged, and then exposed to a light pattern of an original image to selectively discharge the surface in accordance therewith. The resulting pattern of charged and discharged areas on the photoreceptor form an electrostatic charge pattern, known as a latent image, conforming to the original image. The latent image is developed by contacting it with a finely divided electrostatically attractable powder known as “toner.” Toner is held on the image areas by the electrostatic charge on the photoreceptor surface. Thus, a toner image is produced in conformity with a light image of the original being reproduced. The toner image may then be transferred to a substrate or support member (e.g., paper), and the image affixed thereto by fusing the toner image to the paper to form a permanent record of the image to be reproduced. Subsequent to development, excess toner left on the charge retentive surface is cleaned from the surface. The process is useful for light lens copying from an original or printing electronically generated or stored originals such as with a raster output scanner (ROS), where a charged surface may be imagewise discharged in a variety of ways.
Several components in the electrophotographic printing process described above are in the form of polymeric rolls and belts. Fusing rolls which are used to fix the toner image on a substrate represent a component that is typically in the form of polymeric rolls and belts. Also included among these components are bias charge rolls (BCRS) and bias transfer rolls (BTRs) which electrostatically charge the photoreceptor. Other forms of polymeric rolls and belts include the pressure or backup roll used with a fusing roll to fix the toner image on a substrate. Another form of a polymeric rolls and belts are donor rolls which transfer oil to the fuser roll that assists in releasing the toner from the fuser roll. A further form of polymeric rolls and belts include intermediate transfer rolls and belts that transfer developed images. Another form of polymeric rolls and belts include photoconductive belts and rolls. Other forms of polymeric rolls and belts include those belts and rolls used in Hybrid Scavangeless Development (HSD) as disclosed in U.S. Pat. No. 4,868,600 to Hays et al. and in U.S. Pat. No. 5,172,170 to Hays et al., the relevant portions thereof incorporated herein by reference. All of these a polymeric rolls and belts are typically manufactured by spraying or by dipping
A particularly difficult polymeric rolls and belts to manufacture are fuser rolls and belts. The elevated temperatures and pressures of these rolls and the accurate size and finish requirements necessary to insure proper copy quality make their manufacture difficult.
The fusing of the toner image to the paper to form a permanent record of the image is an important part of the xerographic process. Fusing of the toner image is typically done by heat fixation. The heat fixation may be in the form of radiation, conduction, convection or induction. Most modern xerographic processes utilize conduction heating of the toner image to adhere the image to the paper. This is performed by a fusing roll in contact with the toner image. A fusing roll is placed in rolling contact with a backup roll forming a nip therebetween. The paper having the toner image lying thereon is fed between the rolls through the nip. Heat from the fusing roll together with the pressure within the nip between the fuser roll and the backup roll serve to fuse the image to the paper. Heat is typically applied internally within the roll and is transferred through the substrate of the roll onto the periphery of the roll and onto the paper. The rolls typically include a thermally conductive substrate with a surface layer which is also thermally conductive. To assure uniform transfer of the image onto the paper, typically the fuser roll coating is conformable to the paper. For example, the coating may be in the form of a rubber or polymer material, e.g. a fluoroelastomer coating.
Applying fluoroelastomer and other rubber type coatings to fuser roll substrates are fraught with many problems. The coating may be applied to the substrate by 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.
Spraying is the typical method for the manufacture of fluoroelastomer rollers. The spraying process is very slow and costly. Also, the spraying process requires having the coating solution in a form that is very volatile including many volatile organic chemicals. Further, the spraying process is very prone to air pockets or pits forming in the coating. These pits or air pockets in the coating material of the roll result in improper fusing and poor image quality. Because of the nature of the spray process, much of the coating material is lost in the atmosphere requiring an excess amount of the expensive coating material utilized. Also, the loss of the volatile chemicals result in expensive containment costs for systems to contain the volatile chemicals as well as disposal costs of these materials. This invention is intended to alleviate at least some of the above-mentioned problems for at least some of the several components in the electrophotographic printing process described above which are in the form of polymeric rolls and belts.
Recently a process has been attempted to drip material over a horizontally rotating cylinder. With this process a portion of the material adheres to the cylinder and the remainder drips from the cylinder. The amount of material added to the roll is not precisely controlled as the percentage that adheres varies as parameters change over the production run. Also the material forms a wavy surface where the material is poured.
Recently, a new process has been developed for the spiral coating of polymeric printer roll and belt components. It is more fully described in U.S. Pat. No. 5,871,832 which reference is totally incorporated herein by reference and which is assigned to the same assignee as the instant application.
Referring now to
FIG. 11
, a prior art leveling device for use with the flow coating process for manufacturing polymeric printer roll and belt components is shown. The leveling apparatus
1
A utilizes a blade
2
A including a fixed end
3
A which is attached to an axially moving slide
4
A on the first end
3
A of the blade
2
A. The blade
2
A includes free end
5
A which flexibly cooperates with a coating
6
A placed on a surface
7
A of a roll
8
A. The coating
6
A is placed between the free end
5
A of the blade
2
A and the roll
8
A. The flexible blade
2
A is utilized to more evenly distribute the coating
6
A on the roll
8
A.
The flow coating process utilizing the blade having a free end and shown in
FIG. 11
is generally successful in providing accurate coatings to roll and belt components. However, the use of the blade with a free end has certain difficulties. One of these problems is that the free end blade has only limited control over the tension or force applied by the blade
2
A against the roll. The blade thickness may be changed as well as the deflecting angle of the blade but both adjustments are crude and not particularly reliable. Further, the free end of the blade is subject to wear which may be quite rapid on the blade. The wear on the blade may affect the force that the blade applies to the coating and the effectiveness of the blade. The present invention is directed to alleviate at least some of the aforementioned problems.
The following disclosures may be relevant to various aspects of the present invention:
U.S. Pa
Russell, Jr. James G.
Schmitt Sandra L.
Zufelt Craig A.
Dixon Merrick
Ryan Andrew D.
Xerox Corporation
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