WO1999030211A1

WO1999030211A1 - Improved fluid delivery device

Info

Publication number: WO1999030211A1
Application number: PCT/US1998/025428
Authority: WO
Inventors: Richard Andrew Bucher
Original assignee: Gore Enterprise Holdings, Inc.
Priority date: 1997-12-05
Filing date: 1998-12-01
Publication date: 1999-06-17
Also published as: AU1539999A

Abstract

The present invention is directed to a novel improved fluid delivery device (10) comprising a support member such as a shaft (12), a fluid (16) holding material such as a foam or other absorbent porous material (14), surrounding the support member, and a fluid permeation control layer (18, 20) comprising a microporous material adjacent the fluid holding material.

Description

TITLE OF THE INVENTION

IMPROVED FLUID DELIVERY DEVICE

FIELD OF THE INVENTION

The present invention is directed to improved fluid delivery devices. These improved devices can be used to apply fluid to any number of surfaces where a controlled rate of fluid delivery is important.

BACKGROUND OF THE INVENTION

Devices which permit the smooth and easy release of materials have long been sought for a wide variety of applications. For example, continuous belts are used to transfer a wide variety of items, ranging from molded parts to baked goods, from one location to another. In order to minimize or eliminate sticking of items to a surface, the material chosen is critical. Fluid delivery devices which deliver fluids such as release agents to surfaces are examples of devices which have been developed to meet this need. A further advantage of such fluid delivery devices is that they may be used to deliver chemical agents other than, or in addition to, release agents to a surface. In the field of non-impact printing, particularly in non-impact printing devices including, but not limited to, photocopiers, laser printers, thermal printers, ink jet printers, dye sublimation printers, fax machines, and the like, collectively referred to for convenience herein as "printers," fluid delivery devices are used in a number of locations for delivering release agent to critical imaging surfaces in the printer. A "critical imaging surface" is defined as any surface that is involved with the formation, transfer or fixing of the image. These surfaces include but are not limited to, photoreceptors, transfer belts or drums, fuser rollers, pressure rollers, fixing or fuser belts, and paper or other printing medium. For example, one location where a fluid delivery device may be used to deliver release agent to a critical image surface is in the fuser area of the printer where the image is fixed or fused to the paper or other printing medium. A heated roller or belt is used to melt the toner. Typically the fuser roller is pressed against an elastomeric pressure roller. The nip formed between the fuser and the pressure roller provides the pressure to force the melted or softened toner into the printing medium (i.e., paper or the like). This process fixes the image to the paper. It is important to ensure that the image stays with the paper and does not stick to the pressure or fuser rollers. If toner sticks to the fuser roller and is not cleaned off before the next image passes through the copier, an unwanted spot of toner can be formed on the subsequent image. This unwanted spot is referred to as "off-set."

In order to prevent off-set from occurring, a release agent is typically applied to the fuser or pressure roller. The release agent is typically silicone oil, or a mixture of silicone oil and a surfactant or solvent. It is important that the release agent is applied uniformly across the surface of the fuser roller to prevent offsetting.

Aramid fiber (e.g., NOMEX® fiber) release agent delivery devices have been used extensively in printers for many years. The devices come in a variety of geometries suited for the needs of various printer machines, including non-woven webs, and woven or felted stationary wicks. Unfortunately, NOMEX®-type fibers are coarse and do not have the ability to adequately control the rate of oil delivery. In many of the applications, the NOMEX® fibrous material is saturated with silicone oil and then pressed against the fixation roller. These devices deliver an inconsistent amount of oil and can be very abrasive on the fixation roller surface. In addition, NOMEX® fiber web materials come in many different forms, all of which have extremely high variations in density and thickness. These variations cause oiling irregularities and fluctuations that cannot be tolerated. Other problems with these forms of fluid delivery devices may include:

1) Decreasing oil delivery over the life as the oil drains out;

2) Oil leaking out in null periods, leading to high initial oil rates;

3) Pores clogging with dirt over time, which will adversely affect the oil delivery; 4) Building up of static electric charges when electrically insulative material is used;

5) Premature wearing of the fuser roller due to abrasive surface and high contact pressures; and 6) Poor efficiency of oil transfer.

Other stationary oil delivery devices attempt to improve the oil delivery rate and reduce the abrasion of the NOMEX® by covering the NOMEX® felt with a protective cover, such as an expanded polytetrafluoroethylene (ePTFE) membrane. These devices have limitations in operating life and demonstrate significant inconsistencies in oil delivery over the operating life.

Significant improvement in performance has been achieved by applicants in stationary fluid delivery device designs by mounting oil delivery media into a tube of expanded polytetrafluoroethylene (PTFE). Such devices are described in U.S. Patent No. 5,478,423, which issued on January 26, 1995, and copending United States Patent Application Serial No. 08/127,670.

As mentioned above, while conventional devices may be able to deliver high amounts of fluid to a surface, such as paper, the rate of fluid delivery is inconsistent from page to page and even across the surface of the page. This results in periodic offsetting and other problems. In the case of release agent, it is important that the release agent be evenly distributed over the surface of the critical imaging surface. This is even more critical with color copiers and printers where there is a much higher percentage toner coverage of the image on the paper. If there are any areas on the critical imaging surface that do not have enough release agent, offsetting may result. For example, most text, black and white images have only 5 to 10% coverage typically, whereas a full color picture images may have as much as 70% to 100% coverage.

The trend in the non-impact printing industry is toward color copiers and printers. The color images typically have a much higher percent toner coverage on the paper, thus requiring the use of higher amounts of toner which increases the chances of off-setting. It is therefore very important to ensure uniform release agent distribution over the surface of the critical image surface. In addition, color images typically require more release agent to ensure good image quality. For example with a 25-35 copy per minute monochrome copier, an equivalent release agent delivery rate of 0.5 to 1 mg/pg may be acceptable to ensure good image quality. However, with a color copier, 2-10 mg/pg may be needed to ensure good image quality. Thus, the need for higher levels of consistent release agent delivery puts a greater demand on the performance of the fluid delivery device. Many complicated and complex systems containing oil reservoirs, pumps, wicks, and wipers, have been engineered in attempts to uniformly deliver higher rates of fluid, such as release agent. These systems are costly and still do not provide the uniformity of release agent delivery needed for most applications.

Still yet, other devices have been developed to more efficiently deliver the release agent, such as those described in United States Patent Nos. 5,482,552 to H. Kikukawa, and 5,232,499, to H. Kato. These patents teach simple devices which are designed to deliver low amounts of release agent over long periods of time. The typical rate of consistent delivery is in the 0.01- 0.5 mg/pg range, which is acceptable for some monochrome systems but would not be sufficient for most color system. These devices use a mixture of silicone rubber and release agent in the support material, which prevents the release agent from migrating or dripping from the device. Although very effective in maintaining the release agent, the presence of the rubber component in the mixture greatly reduces the amount of release agent that can be delivered. Finally, these devices include a microporous membrane to control the rate of delivery of the release agent. However, as stated earlier herein, the release agent delivery rate achieved with this construction is far too low for most color applications.

Thus, to date, there has not been available a fluid delivery device which is capable of delivering high amounts of fluid at consistently uniform rates, which would allow the use of such fluid delivery devices in highly demanding applications, including but not limited to non-impact color printer devices.

SUMMARY OF THE INVENTION

The present invention is directed to a novel improved fluid delivery device, wherein the device is, among other things, capable of delivering high levels of fluid to a surface. The novel fluid delivery device comprises a support member, such as a shaft, a fluid holding material, such as a foam or other absorbent material, surrounding the support member, and a fluid permeation control layer comprising a microporous material adjacent the fluid holding material, and preferably adhered to at least a portion thereof. As used herein, the term "microporous" is intended to mean a continuous sheet of material that is at least 50% porous (i.e., it has a pore volume of > 50%) with 50% or more of the pores being no more than about 10 μm in nominal diameter. The device may optionally also comprise a liquid barrier material to assist in retaining the fluid within the device, as described in more detail herein. The fluid delivery device of the present invention can deliver fluid uniformly to a surface in a controlled manner. The control of the delivery comes from the permeation control layer. The permeation control layer is a microporous membrane encapsulating the fluid filled support material. The term "microporous membrane," as used herein, is intended to mean a continuous sheet of material that is at least 50% porous (i.e., it has a pore volume of >50%) with 50% or more of the pores being no more than about 5 μm in nominal diameter.

There are a number of microporous membranes that are suitable for this invention such as ultra high molecular weight PE, ePTFE and sintered granular PTFE, and the like. A preferred permeation control layer is expanded polytetrafluoroethylene, or ePTFE. This material is preferred because of the consistency of the microstructure, good chemical stability, good thermal stability, and high strength. The microstructure of the ePTFE can be controlled for a given application. If higher levels of fluid delivery are required, a larger pore size of ePTFE can be used. The ePTFE is an inert material, and will be chemically resistant to most acids and bases. In addition, the ePTFE microporous membrane of the present invention is very thermally stable, and can be used at a constant operating temperature of about 250°C, without any degradation. This temperature stability allows the ePTFE to be used in direct contact with fuser rollers, which are typically heated to 160°C to 220°C. Finally, the ePTFE microporous material of the present invention is strong and durable. The node and fibril structure of the ePTFE, as shown in Figure 3, creates a network which possesses high strength. The nodes 42 of the ePTFE 44, are interconnected with fibrils 46, and the pores 48 are created by the open spaces within the structure. The ePTFE microporous material of the present invention will vary in structure depending on the application. The preferred thickness however is in the 0.0005 inch to 0.050 inch (0.013 to 1.27 mm) range with the most preferred thickness being 0.001 inch to 0.025 inch (0.025 to 0.6 mm). The preferred porosity of the ePTFE microporous material of the present invention is 60-95% with the most preferred porosity being 70-90%.

The microporous permeation control layer of the fluid delivery device of the present invention provides very uniform fluid delivery. In most systems, felts and fabrics have been used to deliver the release agent; however, the typically coarse, non-uniform structure of these materials does not provide the uniformity of delivery required for most applications.

Finally, the fluid delivery device of the present invention may contain a liquid barrier which assists in retaining fluid within the device. For example, when the roller is held in other than a horizontal position, whether during rest between printer operation, during storage, or the like, the fluid barrier assists in retaining fluid in localized regions within the roller and minimizes variations in fluid concentration within the roller due to gravitational forces so as to minimize seepage. One or more fluid barriers may be positioned at selected locations along the length of the roller.

In a particularly preferred embodiment of the present invention, the fluid delivery device of the present invention is in the form of a liquid release agent metering and coating roller comprising a microporous permeation control material comprising porous polytetrafluoroethylene (PTFE) adhered to the outer surface of a porous open-celled support material containing in its pores a liquid release agent, wherein upon installation within a non-impact printer said printer delivers the liquid to a sheet (e.g., an 8 A inch by 11 inch sheet of paper) at a uniform rate of greater than 1 mg/sheet for at least 10 sheet when the printer operates at a speed equal to or greater than 2 sheets per minute, more preferably at a uniform rate of greater than 5 mg/sheet, even more preferably at a uniform rate of greater than 10 mg/sheet, even more preferably at a uniform rate of greater than 20 mg/sheet, and most preferably at a uniform rate of greater than 30 mg/sheet.

In use within a printer, the preferred roller configuration of the fluid delivery device of the present invention may be positioned to be pressed against the fuser roller of the printer. In a roller form, the fluid delivery device of the present invention rotates freely with the rotation of the fuser roller and uniformly delivers the release agent. The fluid delivery device of the present invention is an improvement over what is typically used because it can simply and uniformly deliver high rates of oil.

An advantage of the fluid delivery device of the present invention is that it can uniformly deliver high rates of oil, in the range of greater than 1 mg/sheet, preferably greater than 30 mg/sheet, and up to as high as 100 mg/sheet, or greater, for at least 10 sheet of printing medium.

In one embodiment, the fluid delivery device of the present invention may be configured to securely contain a predetermined quantity of the fluid in the device, thus eliminating the need for fluid reservoirs, tubing, pumps, etc. One advantage to the improved fluid delivery device of the present invention is that due to the high fluid holding capability, the device can be more easily serviced/replaced with minimal effort, as fluid reservoir tubing, pumps, and other periphery devices do not have to be disconnected and then reconnected to change out the fluid delivery device, thus greatly reducing the time needed for service and the number of parts required for manufacture. However, depending on the fluid delivery requirements, it is still possible to include such fluid reservoirs in combination with the present device.

BRIEF DESCRIPTION OF THE FIGURES The operation of the present invention should become apparent from the following description when considered in conjunction with the accompanying drawings, in which:

Figure 1 is an isometric view of a preferred fluid delivery device of the present invention; Figure 2 is a cross sectional view of a fuser unit of a printer incorporating the fluid delivery device of the present invention;

Figure 3 is a scanning electron micrograph at 5,000x magnification of expanded PTFE;

Figure 4 is a scanning electron micrograph at 10,000x magnification of sintered PTFE particles;

Figure 5a is a side view of a fluid delivery device of the present invention incorporating liquid barriers positioned along the axis of the device, and Figure 5b is a perspective view of a liquid barrier shown in Figure 5a; Figures 6a-6f show isolated views of the components of the fluid delivery device and optional alternative geometries;

Figure 7 is an isometric view of a fluid delivery device of the present invention with the permeation control layer axially wrapped in a cigarette roll fashion over the support layer;

Figure 8 is an isometric view of a fluid delivery device of the present invention with the permeation control layer spirally wrapped over the support layer;

Figure 9 is an isometric view of a fluid delivery device of the present invention prior to complete attachment of the permeation control layer, showing a discontinuous adhesive on the support material layer;

Figure 10 is an isometric view of a fluid delivery device of the present invention prior to complete attachment of the permeation control layer, showing a discontinuous adhesive on the permeation control layer; Figure 11 is a side view of a dimpled heated roller used to form a discontinuous bond between the support layer and the permeation control layer;

Figure 12 is an isometric view of a fluid delivery device of the present invention with a tubular permeation control layer partially pulled over the support material;

Figure 13 is a side view of a fluid delivery device of the present invention with the liquid barrier between sections of the support material and sealed to the end of the fluid delivery device with an adhesive;

Figure 14 is a side view of a fluid delivery device of the present invention with the liquid barrier between sections of the support material and sealed to the end of the fluid delivery device with the permeation control layer pulled over it;

Figure 15 is a side view of the fluid delivery device of the present invention with the liquid barrier being formed in situ in a space between support material sections;

Figure 16 is a side view of the fluid delivery device of the present invention with the liquid barrier being formed in situ in the support material; Figure 17 is a side view of the fluid delivery device of the present invention with a section of the support material having liquid barriers formed on the ends;

Figure 18 is a side view of the fluid delivery device of the present invention with liquid barriers comprising spaces between sections of the support material;

Figure 19 is a side view of the fluid delivery device of the present invention with continuous melted sections of the support material as the liquid barrier; Figure 20 is a side view of the fluid delivery device of the present invention with discontinuous melted sections of the support material as the liquid barrier;

Figure 21 is a side view of the fluid delivery device of the present invention with the permeation control layer thermally sealed to the end of the fluid delivery device; and

Figures 22A and 22B are side views of two alternative embodiments of the fluid delivery device of the present invention further incorporating an optional reservoir for additional fluid storage.

DETAILED DESCRIPTION OF THE INVENTION

Referring to Figure 1 , the fluid delivery device 10 of the present invention preferably comprises a shaft 12, porous support material 14 imbibed with a fluid 16, and a permeation control layer 18. The fluid delivery device may also optionally comprise at least one liquid barrier 20 which assists in retaining fluid within the device.

A preferred fluid delivery device of the present invention may comprise a release agent fluid delivery device which is placed in contact with a critical imaging surface of a printer in order to deliver the fluid to the critical imaging surface. Figure 2 depicts a cross-sectional view of a fuser unit within a printer incorporating a fluid delivery device. Specifically, the fuser 31 typically comprises a heated roller, or fuser roller 33, a pressure roller 35, and a release agent delivery device 10 of the present invention. The release agent delivery device 10 is pressed into contact with the fuser roller 33 and will rotate freely with the fuser roller 33. As the release agent delivery device 10 rotates, release agent 39 is delivered to the fuser roller 33 and ensures that the toner 37 present on the printing medium 40 will not adhere to the fuser roller 33. If there is not an adequate amount of release agent 39, on the fuser roller 33, the toner 37 can adhere to the fuser roller 33, thus allowing for the possibility of undesirable offsetting to occur on subsequent pages. It is therefore critical that the release agent delivery device 10, consistently delivers release agent 39 uniformly to the fuser roller.

The fluid delivery device of the present invention can deliver fluid uniformly to a surface in a controlled manner. The control of the deliver comes from the permeation control layer permeation control layer. The permeation control layer comprises a microporous material encapsulating the fluid filled support material. The term "microporous," as used herein, is intended to mean a continuous sheet of material that is at least 50% porous (i.e., it has a pore volume of >50%) with 50% or more of the pores being no more than about 10 μm in nominal diameter). There are a number of microporous materials which may be used as the permeation control layer of the present invention, including ultra high molecular weight polyethylene, expanded polytetrafluoroethylene (ePTFE), sintered PTFE, and the like. In a particularly preferred embodiment, the permeation control layer comprises ePTFE. This material is preferred because of the uniform consistency of the microstructure, its good chemical stability, good thermal stability, and high strength. The microstructure of the ePTFE can be tailored to meet the specific requirements of a given application. For example, if a higher amount of fluid delivery is needed, a more open pore size of ePTFE can be used. Additionally, because ePTFE is an inert material, it will be chemically resistant to most acids and bases. Further, the ePTFE microporous membrane of the present invention is very thermally stable, and can be used at a constant operating temperature of 250°C, without any degradation. This is temperature stability allows the ePTFE to be used in direct contact with fuser rollers, which are typically heated to 160°C to 220°C. Finally, the ePTFE microporous material of the present invention is strong and durable. The node and fibril structure of the ePTFE, as shown in Figure 3, creates a network which possesses high strength. The nodes 42 of the ePTFE 44, are interconnected with fibrils 46, and the pores 48 are created by the open spaces within the structure. The ePTFE microporous material of the present invention will vary in structure depending on the application. The preferred thickness however is in the range of 0.0005 inch to 0.050 inch (0.013 to 1.27 mm) range with the most preferred thickness being 0.001 inch to 0.025 inch (0.025 to 0.6 mm). The preferred porosity of the ePTFE microporous material of the present invention is about 60-95%, with the most preferred porosity being in the range of 70-90%.

Preferably, the microporous membrane comprises an ePTFE membrane including an expanded network of polymeric nodes and fibrils is made in accordance with the teachings of the United States Patent Nos. 3,953,566, 3,962, 153, 4,096,227, and 4,187,390, and PCT Publication No.

97/06206. This material is commercially available in a variety of forms from W. L. Gore & Associates, Inc., of Elkton, MD, under the trademark GORE-TEX®.

The preferred ePTFE membrane of the present invention is made by blending PTFE fine particle dispersion, such as that available from E.I. duPont de Nemours & Company, Wilmington, DE, with hydrocarbon mineral spirits. The lubricated PTFE is compacted and ram extruded through a die to form a tape. The tape can then be rolled down to a desired thickness using calendering rollers and subsequently dried by passing the tape over heated drying drums. The dried tape can then be expanded both longitudinally and transversely at elevated temperatures above the glass transition temperature of the PTFE (greater than 300°C), at a high rate of expansion, e.g., approximately 100 to 10,000% per second. Moreover, depending on the desired application, one or more fillers may be incorporated with the ePTFE to alter the chemical, thermal or electrical properties of the material. As shown in Figure 4, another suitable microporous material for use as the permeation control layer is sintered PTFE particles. The PTFE particles 51 are fused or sintered together to create a uniformly porous material 53. The pores 55 of the sintered PTFE particle material are created by the spaces between the particles. This material is chemically and thermally stable due to the nature of the PTFE particles. Moreover, the pore size of the material can easily be adjusted by changing the particle size of the PTFE used, and other processing conditions. The preferred thickness for the sintered PTFE microporous material is 0.010-0.10 inch (0.25-2.5 mm) with most preferred being 0.020-0.060 inch (0.5-1.5 mm). The preferred porosity is 30-90% with the most preferred being 50-80%.

This sintered porous PTFE material is described in PCT/GB92/01958. Specifically, this material is a non-expanded PTFE material and comprises particles of PTFE that are sintered together to form a coherent matrix of particles and voids. This isotropic material has relatively large pore size and exhibits homogeneous wicking properties in the through direction and the plane direction. Additionally, the larger pore size means that low viscosity oil, for example, 50 to 100cst, may not be retained within the pores. The support material of the present invention holds the fluid to be delivered by the device. Therefore, depending on the desired performance, the support material can be tailored for each application. The support material may comprise a felt, a foam, a fabric or a microporous membrane, or the like. Suitable compositions of the material include, but are not limited to, polyester, polyethylene, polyurethane, silicone, or the like, with the preferred support material being a silicone or polyurethane foam having a porosity greater than 50% and a density of 3 to 5 kg/m³, and capable of holding up to about 0.5 to 0.99 cnτVcm³ of liquid, or higher.

The fluid delivery device of the present invention may contain a liquid barrier within or adjacent the support material. This liquid barrier assists in retaining fluid within localized regions of the device and prevents the liquid from migrating from one section to another, which can be extremely important during use, storage and/or transport of the fluid delivery device. For example, when the roller is held in other than a horizontal position, whether during rest between printer operation, during storage, or the like, the fluid barrier assists in retaining fluid in localized regions within the roller and minimizes variations in fluid concentration within the roller due to gravitational forces so as to minimize seepage.

One or more fluid barriers may be positioned at selected locations along the length of the roller. The liquid barrier may be a disk or other suitable form of material that is impermeable, or resistant to the transfer of the fluid. The liquid barrier may be a film disk, a closed cell foam, a microporous material, a fused impermeable region, or a ring of impermeable material applied in situ. In addition, the liquid barrier may be a space between sections of the support material which prevent the transfer of fluid from one section to another. A preferred liquid barrier is a film disk, such as a PFA or polyester disk. The liquid barrier 57, as depicted in Figure 5, is placed between sections of the support material, and may also be placed on ends of the device. The type of liquid barrier used is chosen depending on the requirement of the specific application.

The shaft of the present invention can be defined as a rigid support that allows for the rotation of the fluid delivery device of the present invention. As shown in Figure 6a, the shaft in its simplest form may be a hollow tube, or as shown in Figure 6b, a solid shaft. As shown in Figure 6c, in some cases it may be necessary for the shaft to be perforated. Another embodiment comprising a screen type tube is shown in Figure 6d. Finally, the shaft may have any suitable geometry, including circular, as depicted in Figures 6a-d, square as depicted in Figure 6e, or triangular as depicted in Figure 6f. In some cases, the fluid may be pumped through the shaft and delivered to the support material through perforations or openings in the shaft. This embodiment allows the fluid delivery device of the present invention to operate continuously with the supply of fluid through the shaft.

The fluid delivery device of the present invention is designed to deliver fluid to a surface. The fluid may be a chemical solution, solvent, oil, or water. For printer applications, a release agent fluid is typically delivered to the fuser roller, and the release agent typically comprises silicone oil. In some cases, the silicone oil is functionalized (i.e., amino, fluoro, or mercapto functionalized oil). The viscosity of the silicone oil used may vary from application to application.

The permeation control layer of the fluid delivery device of the present invention can be applied to the support material in a number of ways. As shown in Figure 7, the permeation control layer 18 may be in a sheet form that is wrapped around the support material and sealed along the length of the axis of the roller 60. As shown in Figure 8, the permeation control layer 18 may also be spirally wrapped along the length of the axis of the roller 60. In both cases, the permeation control layer 18 may be adhered to the surface of the support material a number of ways. The support material may contain an adhesive on its surface that when wrapped with the permeation control layer at least partially imbibes the permeation control layer. When the adhesive is cured, the permeation control layer and the support material will be adhered. The adhesive in the support material may be a mixture of a fluid such as silicone oil, and adhesive such as silicone rubber adhesive. Furthermore, as shown in Figure 9, the adhesive 62 may be applied to the surface of the support material 14 in a discontinuous pattern prior to wrapping the permeation control layer 18 onto the roller 60. As shown in Figure 10, in some cases, the adhesive 62 may be applied directly to the permeation control layer 18 prior to wrapping the permeation control layer over the support material 14 of the roller 60. Yet another method of adhering the permeation control layer to the support material utilizes heat. As shown in Figure 11 , heat can be applied to the permeation control layer 18, such as through the use of a heated roller 66, in such a way as to cause the lower melting point support material to melt and flow into the permeation control layer 18, thereby creating a physical bond at isolated points 64 where the support material is imbibed in the permeation control layer 18. The heat would preferentially be applied to localized areas, in order to maintain the majority of the surface permeable for fluid delivery.

As shown in Figure 12, in another embodiment, the permeation control layer 18 may be in the form of a continuous tube. The microporous tube may be pulled over the support material 14 and fixed at the ends with an adhesive or adhered over the surface of the support material with an adhesive as described above. The adhesive may be applied to the support material or the microporous tube, and may be discontinuous or continuous. In some cases, the microporous tube may fit snugly over the support material such that no adhesive is needed.

The liquid barrier of the present invention, as described in more detail earlier herein, can be incorporated into the fluid delivery device in a number of ways. As shown in Figure 13, when the liquid barrier 70 is in the form of a disk, during formation of the device, the liquid barrier disk 70 can be slid over the shaft 12 and placed between sections of the support material 14. The number and spacing of the liquid barriers depends on the volume of support material and the amount of fluid held. In a preferred embodiment, a liquid barrier placed every 2" (5.1 cm) is sufficient to ensure uniformity of the fluid within the fluid delivery device. The liquid barrier pieces may also be adhered into place with any suitable adhesive , and the adhesive may be applied to one or more surfaces of the liquid barrier, such as the face surface, the inside diameter or the outside diameter. As shown in Figure 13, when the liquid barrier 70 is applied to the ends of the fluid delivery device, an adhesive 72 may be applied to the inside face surface of the liquid barrier 70 in order to adhere it to the support material. Further, as shown in Figure 14, the permeation control layer 18 may be pulled over the outside of the liquid barrier 70 and adhered to the liquid barrier 70 to seal the device.

Another suitable liquid barrier of the present invention is a polymer material or adhesive formed in situ, in the fluid delivery device. The material may be a hot melt adhesive or a silicone rubber that will become a solid over time. As shown in Figure 15, the in situ type liquid barrier 75 can be applied by injecting the liquid barrier 75 through a nozzle 77, or the like, in a space 79 between sections of the support material 1 , or alternatively, as shown in Figure 16 directly into the support material 16. When the in situ liquid barrier 75 is applied directly to the support material 16, it will wick through the support material 16 to form a substantially impermeable liquid barrier 75. Further, as shown in Figure 17, the liquid barrier 75 may be applied to one or more ends of a support material section 16 prior to assembly. The support material is porous and will readily pick up a curable or solidifying material, as described earlier herein.

As shown in Figure 18, yet another type of liquid barrier is a space 82 between sections of the support material 16. The support material sections may be assembled in such a manner as to provide spaces which will substantially reduce the rate of migration of the fluid. As with the liquid barrier, the size and number of spaces depends on the amount of fluid being held in the support material and the configuration of the fluid delivery device.

Furthermore, the liquid barrier may be formed by altering regions of the support material by melting and substantially reducing or closing off pores within the support material, such as through the application of heat. In many cases the support material is a heat sensitive material that will melt or deform when heated. In one embodiment , the ends of sections of support material may be subjected to heat or comparable energy, such as a hot knife, hot air laser or other heat producing device in order to melt and substantially, reduce the permeability of the support material at the ends. In addition, it may be possible in some cases to melt the support material after the device is assembled in place. For example, as shown in Figure 19, a hot knife 85 could be used to melt the support material 16 at specific locations. As shown in Figure 19, the resulting liquid barrier 86 formed may be either a continuous liquid barrier region 86, or as shown in Figure 20, may include a space 88 between the liquid barrier regions 86.

The ends of the fluid delivery device can be sealed a number of ways. As described earlier, a liquid barrier disk can be adhered to the ends of the fluid delivery device. In addition, an in situ type liquid barrier, may be applied to the ends of the support material as described above. Alternatively, an in situ type material may be applied to the permeation control layer at the ends of the fluid delivery device. This will seal the ends and adhere the permeation control layer at the ends. Heat could be used to seal both the permeation control layer to the support material at the ends, and render the end of the fluid delivery device substantially impermeable to fluid. As shown in Figure 21 , a heated element 90 could be pressed against the end of the fluid delivery device 92, which would cause the support material 16 to melt and flow into the permeation control layer 18, thereby forming the liquid barrier 95. Any combination of liquid barrier configurations may be incorporated into a single fluid delivery device, depending on the desired application requirements.

The support material can be adhered to the shaft with any conventional methods. Adhesive may be applied to the shaft prior to placing the support material over it. Adhesive may be applied to the through hole of the support material. In some cases, the geometric fit of the support material over the shaft may provide enough support that no adhesive is needed. The adhesive may be a hot melt, such as polyester, polyamide, nylon and the like, or a curable type such as a urethane, or silicone.

Depending on the desired life and/or liquid delivery rates of the fluid delivery device of the present invention, it would be possible to provide a reservoir of additional fluid, such as that shown in Figures 22A and 22B, showing a gravity feed and pump supplied configuration, respectively. The fluid 112 stored in the reservoir tank 114 is delivery either by a gravity feed hose 116 (Fig. 22A) or by a pump and hose configuration 118 (Fig. 22B) through a slip ring 120 and into the perforated hollow shaft 122 of the fluid delivery device 124.

The fluid delivery device of the present invention may be used to deliver a variety of fluids to any number of surfaces such as, but not limited to, a printing medium. In some cases, it may be desirable to coat the paper or other printing medium with a fluid to enhance image quality. For example, in order to improve the wetting and spread of the ink, dye or other imaging material into the paper, a surfactant solution may be applied to the paper. This process may be done prior to the printing, using the fluid delivery device of the present invention. Surfactants, silicone oil, functionalized oil, water and other fluids may be used to improve the wetting characteristics. Alternatively, fluids may be used to reduce the amount of spread of the imaging material. For example, a fluid containing at least in part some wax, acrylic, oil, or the like, may reduce the spread of the ink on the paper. Furthermore, a fluid may be applied to the paper which contains one or more specific chemistries which react(s) with the imaging material, preventing the imaging material from spreading, such as by cross-linking or other chemical reaction. Such techniques may make the image more durable, or help set the image during subsequent fusing processes.

Still another desirable aspect of the fluid delivery device of the present invention may be to apply a wax or other fluid such as an acrylic solution or the like that increases or decreases the gloss of the image. This fluid could be applied prior to or after the imaging or fusing process.

Other fluid applications which may be delivered by the fluid delivery device of the present invention may include adding a protective top coat to the image in order to improve the scratch resistance and general durability, minimizing the curl induced by the imaging and fusing process, providing protection from ultraviolet light or other harmful radiation, etc. These applications are just several examples of how the fluid delivery device of the present invention can be used to improve the image characteristics, both from a visual and durability perspective.

A preferred application of the fluid delivery device of the present invention, is delivering release agent to critical imaging surfaces in a printer. Again, a critical imaging surface is defined as any surface that is involved with generating transferring or fusing. Theses surfaces include but are not limited to, photoreceptors, transfer belts or drums, fuser roll, pressure rolls, fuser belts. The fluid delivery device of the present invention would most likely be used in the fuser area of the copier where the image is fixed or fused to the paper or other printing medium. In the fuser area of the printer, a heated roller or belt is used to melt the toner. Typically the fuser roller is pressed against an elastomeric pressure roller. The nip formed between the fuser and the pressure roller provides the pressure to force the melted or softened toner into the printing medium. This process fixes the image to the paper. It is important to ensure that the image stay with the paper and not stick to the pressure or fuser roller. If toner, sticks to the fuser roller and is not cleaned off prior to a subsequent image coming through, an unwanted spot will be formed on the subsequent image. This unwanted spot is referred to as off-set. In order to prevent this from occurring, a release agent is typically applied to the fuser or pressure roller. The release agent is typically silicone oil, or a mixture of silicone oil and a surfactant or solvent. It is important that the release agent is applied uniformly across the surface of the fuser roller. If the release agent is not evenly applied, offsetting can result.

A preferred configuration of the fluid delivery device of the present invention is to press it against the fuser roller. In a roller form, the fluid delivery device of the present invention will rotate freely with the rotation of the fuser roller and uniformly deliver the release agent. The fluid delivery device of the present invention is an improvement over what is typically used because it can simply and uniformly deliver high rates of oil. The trend in the non-impact printing industry is toward color copiers and printers. The color images typically have a much higher percent coverage on the paper. This increases the chances of off-setting. It is therefore very important to ensure uniform release agent distribution over the surface of the critical image surface. In addition, color images typically require more release agent. For example with a 25-35 copy per minute monochrome copier, an equivalent oil rate of 0.5 to 1 mg/pg may be acceptable. However with a color copier, 2-10mg/pg may be needed. This puts a greater demand on the fluid delivery device. Many complicated and complex systems containing oil reservoirs, pumps, wicks, and wipers, have been engineered in attempt to uniformly deliver these high rates of oil. These systems are costly and still do not provide the uniformity of release agent delivery needed for many applications.

The fluid delivery device of the present invention can uniformly deliver high rates of oil, in the 1 to 30 mg/pg range, or higher. A preferred embodiment of the fluid delivery device of the present invention contains all of the release agent in the device. This eliminates the need for release agent reservoirs, tubing, pumps, etc. The microporous permeation control layer of the fluid delivery device of the present invention is what provides the uniform release agent delivery. In most past systems, felts and fabrics have been used to deliver the release agent and their coarse non-uniform structure does not provide the uniformity of delivery required.

The fluid delivery device of the present invention is a simple solution that eliminates the need for a lot of other components. This makes the fluid delivery device a very cost effective solution.

Method of Determining Rate of Oil Deliver Using Ion Coupled Plasma - Atomic Emission Spectroscopy (ICP AES)

Paper samples (8.5 inch x 11 inch) were placed into clean sample containers. The containers were filled with 30 to 35 mis of solvent grade kerosene (J.T. Baker, Inc., Phillipsburg, N.J.), so that the paper was completely immersed. The vials were then placed in an ultrasonic bath and sonic extracted for 2 hours. A 15 ml aliquot of the extract solution from each sample was then analyzed for total silicon content by ICP-AES. Samples containing known amounts of silicone from 35 to 1200 micrograms/page were found to yield 100% recovery by this procedure. The ICP was calibrated using standards containing polydimethylsilicone dissolved in kerosene to convert the total silicon measured to total silicone. The amount of silicone was reported as total micrograms silicone per each as received sample. The volume of kerosene used for the extraction was taken into account when the results were reported.

A Leeman Labs PS series sequential inductively coupled plasma (ICP) spectrometer was used for the analysis of the kerosene extracts for total silicon. The instrument was calibrated using the 251.611 nm Si line using background subtraction on both sides of the analytical line. Five integrations of 5 seconds each were used for both the standards and samples. A Cetac ultrasonic nebulizer was used with a membrane desolvator to reduce the solvent loading on the plasma. A calibration curve was obtained daily typically using standards from 0 to 110 ppm silicone. This yielded an analysis range of 0 to 3850 micrograms silicone per sample. If the expected range was indicated to be higher, the calibration curve was extended using the appropriate standard. The wide linearity of the ICP-AES technique minimizes errors for samples which cover a wide range in concentration. During the analysis of the samples, the calibration curve slope and intercept were updated every 11 samples and check samples covering the entire analysis range of 35 to 35,000 micrograms of silicone were run every 20 samples. The check samples were analyzed to verify that their results were within <20% of the true value. The average result for each sample was reported along with the standard deviation of the 5 replicate measurements. If blank paper samples were submitted, the results for the samples were corrected for the amount of silicon measured in the blank samples.

A consistent rate of oil delivery is defined by a variation of no more than 50% from the average rate, from page to page, more preferably no more than 25% variation, and most preferably no more than 10% variation.

Without intending to limit the scope of the present invention, the following examples illustrate how the present invention may be made and used:

EXAMPLE 1 A polyurethane foam (with a density of 4.0 kg/m², and a porosity greater than 50% obtained from Vita Olympic, Greensboro, NC) was machined into a hollow cylinder measuring 213 mm by 24 mm (diameter) and adhered to a concentric metal shaft measuring 237 by 6 mm, available from Rogers Foam Corporation, Somerville, MA. Silicone adhesive SLA7401 from GE Corporation was applied in a gravure pattern to an expanded PTFE membrane (thickness 11.7 micron; mass/area 1.74 g/m²), made in accordance with the teachings of PCT Publication No. 97/06206 (W.L. Gore and Associates, Inc., Elkton, MD). The gravure pattern was achieved by forcing the adhesive through an aluminum mesh screen (2 AL 5-6/OF) from Exmet Corporation, Naugatuck, CT. The adhesive coated membrane was wrapped around the foam cylinder using a cigarette type wrap. Both ends of the foam cylinder were sealed by wrapping the PTFE over the ends and then the end was sealed using excess GE SLA7401. The adhesive was cured in a convection oven at 175°C for 30 minutes. A syringe was used to inject 75.21 grams of 100 cs DC 200 Fluid, Dow Corning, Midland Ml, through one end seal and into the foam reservoir. The syringe hole was then sealed with RTV silicone caulk, also from GE Corporation, to prevent leakage.

The formed oil delivery roller was mounted in a modified Drum Maintenance Unit (DMU) from a Tektronix (Wilsonville, Oregon) Phaser 340 color printer. The modified DMU replaced the Phaser 340's conventional oil delivery device. The modified DMU was placed in a Phaser 340 printer. During operation, the modified DMU cams the oil delivery roller into contact with the imaging drum in the 340. While in contact, the drum rotates at a surface speed of 15 inches per second. Upon completion of two rotations, the modified DMU retracts the oil delivery roller from contact with the imaging drum. Oil delivery rates were calculated by analyzing the printed page (which comes into contact with the oiled drum) using Inductively Coupled Plasma, Atomic Emission Spectroscopy (ICP AES). Ten consecutive images were printed using a Microsoft Power Point image composed of a 100% cyan solid fill. The following Table 1 lists the results of oil delivery to a page:

TABLE 1

The highest variability of oil delivery rate from the average rate of 126.8 mg is 4.1 % is shown by copy samples #2 and #7.

EXAMPLE 2 A polyurethane foam (with a density of 4.0 kg/m², and a porosity greater than 50% obtained from Vita Olympic, Greensboro, NC) was machined into a hollow cylinder measuring 213 mm by 24 mm (diameter) and adhered to a concentric metal shaft measuring 237 by 6mm available from Rogers Foam Corporation, Somerville, MA. Silicone adhesive SLA7401 from GE Corporation was applied in a gravure pattern to an expanded PTFE membrane (thickness 65.0 micron; mass/area 17.5 g/m²) made in accordance with the teachings of PCT Publication No. 97/06206 (W.L. Gore and Associates, Inc., Elkton, MD). The gravure pattern was formed by forcing the adhesive through an aluminum mesh screen (2 AL 5-6/OF) from Exmet Corporation, Naugatuck, CT. The adhesive coated membrane was wrapped around the foam cylinder using a cigarette type wrap. Both ends of the foam cylinder were sealed using excess GE SLA7401. The adhesive was cured in a convection oven at 175°C for 30 minutes. A syringe was used to inject 67.97 grams of 100 cs DC 200 Fluid, Dow Corning, Midland Ml, through one end seal and into the foam reservoir. The syringe hole was then sealed with RTV silicone caulk, also from GE Corporation, to prevent leakage

The formed oil delivery roller, was mounted in a modified Drum Maintenance Unit (DMU) from a Tektronix (Wilsonville, Oregon) Phaser 340 color printer, and the oil delivery rate of the roller was determined in accordance with the procedure described in Example 1.

Ten consecutive images were printed using a Microsoft Power Point image composed of a 100% cyan solid fill. The following Table 2 lists the results of oil delivery to a page: TABLE 2

The highest variability of oil delivery rate from the average rate of 28.4 mg is 14.2% is shown by copy sample #4.

EXAMPLE 3

A polyurethane foam (with a density of 4.0 kg/m², and a porosity greater than 50% obtained from Vita Olympic, Greensboro, NC) was machined into a hollow cylinder measuring 213 mm by 24 mm (diameter) and adhered to a concentric metal shaft measuring 237 by 6mm available from Rogers Foam Corporation, Somerville, MA. Silicone adhesive SLA7401 from GE Corporation was applied in a gravure pattern to an expanded PTFE membrane (thickness 65.0 micron; mass/area 17.5 g/m²) made in accordance with PCT Publication No. 97/06206 (W.L. Gore and Associates, Inc., Elkton, MD). The gravure pattern was created by forcing the adhesive through an aluminum mesh screen (2 AL 5-6/OF) from Exmet Corporation, Naugatuck, CT. The adhesive coated membrane was wrapped around the foam cylinder using a cigarette type wrap. Both ends of the foam cylinder were sealed using excess GE SLA7401 (same question?). The adhesive was cured in a convection oven at 175°C for 30 minutes. A syringe was used to inject approximately 75 grams of 350 cs DC 200 Fluid, Dow Corning, Midland Ml, through one end seal and into the foam reservoir. The syringe hole was then sealed with RTV silicone caulk, also from GE Corporation, to prevent leakage.

The formed oil delivery roller was mounted in a modified Drum Maintenance Unit (DMU) from a Tektronix (Wilsonville, Oregon) Phaser 340 color printer, and the oil delivery rate of the roller was determined in accordance with the procedure described in Example 1.

Ten consecutive images were printed using a Microsoft Power Point image composed of a 100% cyan solid fill. The following Table 3 lists the results of oil delivery to a page:

TABLE 3

The highest variability of oil delivery rate from the average rate of 5.74 mg is 3.97% is shown by copy sample #3.

EXAMPLE 4

A polyurethane foam (with a density of 4.0 kg/m², and a porosity greater than 50% obtained from Vita Olympic, Greensboro, NC) was machined into a hollow cylinder measuring 213 mm by 24 mm (diameter) and adhered to a concentric metal shaft measuring 237 by 6mm available from Rogers Foam Corporation, Somerville, MA. Silicone adhesive SLA7401 from GE Corporation was applied in a gravure pattern to an expanded PTFE membrane (thickness 65.0 micron; mass/area 17.5 g/m²) made in accordance with PCT Publication No. 97/06206 (W.L. Gore and Associates, Inc., Elkton, MD). The gravure pattern was made by forcing the adhesive through an aluminum mesh screen (2 AL 5-6/OF) from Exmet Corporation, Naugatuck, CT. The adhesive coated membrane was wrapped around the foam cylinder using a cigarette type wrap. Both ends of the foam cylinder were sealed using excess GE SLA7401 (same question?). The adhesive was cured in a convection oven at 175°C for 30 minutes. A syringe was used to inject approximately 75 grams of 350 cs DC 200 Fluid, Dow Corning, Midland Ml, through one end seal and into the foam reservoir. The syringe hole was then sealed with RTV silicone caulk, also from GE Corporation, to prevent leakage.

As mentioned earlier herein, during shipment to the end user it cannot be guaranteed that the device will always remain in a horizontal position. Thus, leakage prevention must be guaranteed independent of the orientation of the device. A polyethylene film barrier film measuring 6 mils (from McMaster Carr Supply Company, New Brunswick NJ) was wrapped around the oil delivery roller of this example and secured with adhesive tape. The device was then positioned vertically along the axis of the shaft for 72 hours at room temperature. Oil leakage was found to be significant at the end of the test period (i.e., greater than 50% of the oil leaked from the roller).

EXAMPLE 5

A polyurethane foam (with a density of 4.0 kg/m², and a porosity greater than 50% obtained from Vita Olympic, Greensboro, NC) was machined into five hollow cylinders 45 mm in length, 24 mm in outer diameter, and six mm in inner diameter. Thin polymer disks measuring 4 mils and having a composition of polyethylene (Rogers Foam Corporation, Somerville, MA) were provided. The five cylinders, separated axially by the thin polymer disks, were adhered to a concentric metal shaft measuring 237 by 6 mm available from Rogers Foam Corporation, Somerville, MA. A polymer disk was also adhered to each outer end of the foam roller. Silicone adhesive SLA7401 from GE Corporation was applied in a gravure pattern to an expanded PTFE membrane (thickness 65.0 micron; mass/area 17.5 g/m²) made in accordance with PCT Publication No. 97/06206 (W.L. Gore and Associates, Inc., Elkton, MD). The gravure pattern was created by forcing the adhesive through an aluminum mesh screen (2 AL 5-6/0F) from Exmet Corporation, Naugatuck, CT. The adhesive coated membrane was wrapped around the cylinder of foam regions and polymer disks using a cigarette type wrap. The membrane was overlapped at either end and sealed to the outer polymer disks using excess GE SLA7401. To assure good adhesion, a soldering iron was used to apply localized heat to cure adhesive between the membrane and the outer polymer disk surfaces, as well as to cure the adhesive between the membrane and the outer diameters of the internal polymer disks. The entire device was cured in a convection oven at 175°C for 30 minutes.

The device was then placed in a vacuum bag which contained in excess of 100 grams of 350 cs DC 200 Fluid, Dow Corning, Midland Ml. The bag was sealed and a vacuum was drawn in the area immediately adjacent to the device. Upon removal of all air in the device and in the bag, the device was submerged in the oil. Air was then allowed to reenter the bag, inducing oil to transfer into the oil delivery device through the membrane. Approximately 75 grams of oil was introduced into the device.

A barrier film identical to that described in Example 4 was wrapped around this device and secured with adhesive tape. The device was then positioned vertically along the axis of the shaft for 160 hours at room temperature. At the end of the test, it was determined that no oil had leaked from the device.

COMPARATIVE EXAMPLE

An oil roll produced by Japan Gore-Tex Incorporated, (as described in U.S. Patent No. 5,482,552) was tested for comparative performance.

The oil delivery roller was mounted in a modified Drum Maintenance Unit (DMU) from a Tektronix (Wilsonville, Oregon) Phaser 340 color printer. The modified DMU replaced the Phaser 340's conventional oil delivery device. The modified DMU was placed in a Phaser 340 printer. During operation the modified DMU cams the oil delivery roller into contact with the imaging drum in the 340. While in contact the drum rotates at a surface speed of 15 inches per second. Upon, completion of two rotations, the modified DMU retracts the oil delivery roller from contact. Oil delivery rates are calculated by analyzing the printed page (which comes into contact with the oiled drum) using Inductively Coupled Plasma, Atomic Emission Spectroscopy (ICP AES).

Ten consecutive images were printed using a Microsoft Power Point image composed of a 100% cyan solid fill. The following Table 4 lists the results of oil delivery to a page:

TABLE 4

The oil roll was not able to maintain a consistent delivery, resulting in printing failure for prints 8, 9 and 10 due to insufficient oil delivery.

While particular embodiments of the present invention have been illustrated and described herein, the present invention should not be limited to such illustrations and descriptions. It should be apparent that changes and modifications may be incorporated and embodied as part of the present invention within the scope of the following claims.

Claims

WE CLAIM:

1. A fluid metering and coating roller comprising:

(a) a microporous permeation control material comprising porous polytetrafluoroethylene (PTFE) adhered to the outer surface of

(b) a porous open-celled support material containing in its pores

(c) a fluid, wherein upon installation within a non-impact printing device said device delivers fluid at a uniform rate of greater than 1 mg/page for at least 10 pages at a printing speed equal to or greater than 2 pages per minute.

2. The fluid metering and coating device of claim 1 , wherein said device delivers fluid at a uniform rate of greater than 5 mg/page for at least 10 pages.

3. The fluid metering and coating device of claim 1 , wherein said device delivers fluid at a uniform rate of greater than 10 mg/page for at least 10 pages.

4. The fluid metering and coating device of claim 1 , wherein said device delivers fluid at a uniform rate of greater than 20 mg/page for at least 10 pages.

5. The fluid metering and coating device of claim 1 , wherein said device delivers fluid at a uniform rate of greater than 30 mg/page for at least 10 pages.

6. The fluid metering and coating device of claim 1 , wherein said device delivers fluid at a uniform rate of greater than 100 mg/page for at least 10 pages.

7. The fluid metering and coating device of claim 1 , wherein said device delivers fluid at a uniform rate of greater than 1 mg/page for at least 50 pages.

8. The fluid metering and coating device of claim 1 , wherein said porous open-celled support material comprises at least one material selected from the group consisting of polyurethane and silicone.

9. The fluid metering and coating device of claim 1 , wherein said porous open-celled support material has a porosity equal to or greater than 50%.

10. The fluid metering and coating device of claim 1 , wherein said fluid comprises silicone oil.

11. The fluid metering and coating roller of claim 1 , further comprising a reservoir for supplying additional fluid to said roller.

12. A fluid metering and coating device comprising: (a) a microporous permeation control material comprising expanded polytetrafluoroethylene (PTFE) adhered to the outer surface of

(b) a porous open-celled support material containing in its pores

(c) a fluid, and (d) at least one fluid barrier adjacent said porous open-celled support material for retaining said fluid in localized regions within the porous open celled support material.

13. The fluid metering and coating device of claim 12, wherein said device comprises a roller.

14. The fluid metering and coating device of claim 12, wherein upon installation within a photocopier said device delivers fluid at a uniform rate of greater than 1 mg/page for at least 10 pages.

15. The fluid metering and coating device of claim 12, wherein upon installation within a photocopier said device delivers fluid at a uniform rate of greater than 5 mg/page for at least 10 pages.

16. The fluid metering and coating device of claim 12, wherein upon installation within a photocopier said device delivers fluid at a uniform rate of greater than 10 mg/page for at least 10 pages.

17. The fluid metering and coating device of claim 12, wherein upon installation within a photocopier said device delivers fluid at a uniform rate of greater than 20 mg/page for at least 10 pages.

18. The fluid metering and coating device of claim 12, wherein upon installation within a photocopier said device delivers fluid at a uniform rate of greater than 30 mg/page for at least 10 pages.

19. The fluid metering and coating device of claim 12, wherein upon installation within a photocopier said device delivers fluid at a uniform rate of greater than 100 mg/page for at least 10 pages.

20. The fluid metering and coating device of claim 12, wherein said microporous permeation control layer comprises expanded PTFE.

21. The fluid metering and coating device of claim 12, wherein said microporous permeation control layer comprises sintered granular PTFE.

22. The fluid metering and coating device of claim 12, wherein said porous open-celled support material comprises at least one material selected from the group consisting of polyurethane and silicone.

23. The fluid metering and coating device of claim 12, wherein said porous open-celled support material has a porosity equal to or greater than 50%.

24. The fluid metering and coating device of claim 12, wherein said fluid comprises silicone oil.

25. The fluid metering and coating device of claim 12, wherein said fluid comprises at least one release agent selected from the group consisting of oil, organic fluid, synthetic fluid, surfactant and water.

26. The fluid metering and coating device of claim 12, wherein said fluid barrier comprises at least one material selected from the group consisting of nylon, polyethylene, polyurethane, PFA, FEP, silicone, polyester, polypropylene, PVA and PTFE, PET and PEN.

27. The fluid metering and coating device of claim 12, wherein said at least one fluid barrier is positioned within said porous open-celled support material.

28. The fluid metering and coating device of claim 12, wherein a fluid barrier is positioned at each end of the porous open-celled support material.

29. A fluid metering and coating roller comprising:

(a) a microporous permeation control material comprising expanded polytetrafluoroethylene (ePTFE) adhered to at least a portion of the outer surface of

(b) a porous open-celled tubular support material comprising polyurethane foam containing in its pores

(c) silicone oil, (d) a shaft positioned within the porous open-celled tubular support material; and

(e) at least one fluid barrier positioned adjacent said porous open- celled tubular support material for retaining said silicone oil in localized regions within the porous open-celled tubular support material.

30. A fluid metering and coating roller comprising:

(a) a microporous permeation control material comprising expanded polytetrafluoroethylene (PTFE) adhered to the outer surface of

(b) a porous open-celled tubular support material comprising silicone foam containing in its pores (c) silicone oil,

(d) a shaft positioned within the porous open-celled tubular support material; and

(e) at least one fluid barrier adjacent said porous open-celled tubular support material for retaining said fluid in localized regions within the porous open-celled tubular support material.

31. A method of applying a fluid to a critical image surface in a nonimpact printing device comprising: providing a fluid metering and coating roller comprising a microporous permeation control material comprising porous polytetrafluoroethylene (PTFE) adhered to the outer surface of a porous open-celled support material containing in its pores a fluid; installing said fluid metering and coating device in a non-impact printing device; and operating said non-impact printing device, whereby said device delivers fluid at a uniform rate of greater than 1 mg/page for at least 10 pages at a printing speed equal to or greater than 2 pages per minute.

32. The method of claim 31 , wherein said device delivers fluid at a uniform rate of greater than 5 mg/page for at least 10 pages.

33. The method of claim 31 , wherein said device delivers fluid at a uniform rate of greater than 10 mg/page for at least 10 pages.

34. The method of claim 31 , wherein said device delivers fluid at a uniform rate of greater than 20 mg/page for at least 10 pages.

35. The method of claim 31 , wherein said device delivers fluid at a uniform rate of greater than 1 mg/page for at least 50 pages.

36. The method of claim 31 , wherein said porous open-celled support material comprises at least one material selected from the group consisting of polyurethane and silicone.

37. The method of claim 31 , wherein said porous open-celled support material has a porosity equal to or greater than 50%.

38. The method of claim 31 , wherein said fluid comprises silicone oil.

39. The method of claim 31 , further comprising providing a reservoir for supplying additional fluid to said roller.