MXPA99006677A - Fluorocarbon particle coated textiles for use in electrostatic printing machines - Google Patents

Abstract

A textile material (30) whose fibers (32, 34) have been coated, at least in part, with fluorocarbon particles (36) is usable in an electrophotographic printing machine to clean toner particles off a fuser roll, and to supply a toner release agent to the fuser roll. The textile material (30) can include woven goods as well as nonwoven felts and the like. The resultant product has reduced friction and decreased fiber shedding.

Description

FLUOROCARBON PARTICLE COATED TEXTILES FOR USE IN ELECTROSTATIC PRINTING MACHINES CROSS REFERENCE TO RELATED REQUEST The patent application claims the benefits the provisional application of the United States of America 2 60 / 034,847 which was filed on January 27, 1997. description of that provisional patent application, is incorporated herein by reference.

FIELD OF THE INVENTION The present invention is generally directed to textiles coated with fluorocarbon particles for use in electrostatic printing machines. More particularly, the present invention is directed to coated textiles with fluorocarbon particles to be used for cleaning toner particles out of a fuser roller in an electrostatic printing machine. More specifically, the present invention is directed to the use of a textile material coated with polytetrafluoroethylene particles to clean toner particles off a fuser roller and to deliver oil as a toner release agent in an electrostatic printing machine. Fluorocarbon particles are applied to the textile fabric, which may include woven articles, as well as woven textiles. These textiles coated with fluorocarbon particles utilize the interstitial retaining of inherent particles with textiles, while retaining the reduced frictional characteristics of the fluorocarbon membrane coated fabric.

DESCRIPTION OF PREVIOUS ART In the field of electrostatic printing "he knows very well how to register an electrostatic image on a photosensitive member with the subsequent performance of the image visible by the application of electrostatic marking particles, typically referred to as toner. the photosensitive member a sheet of paper with the subsequent fixation of the image on the paper.

To fix or melt the toner on the toner on the paper permanently by heat, the toner temperature is raised to a point at which the toner constituents coalesce and become sticky. This causes the toner to flow to some extent on the fibers or pores of the paper. Then, as the toner cools, the toner solidification occurs so that the toner is firmly bound to paper.

One method for achieving thermal fusion of the toner images on paper has been to pass the pap with the unmelted toner images thereon between a p of opposing roller members at least one of which is internally heated. This heated roller is typically referred to as a fuser roll. During the operation of the fastening system of this type, the paper on which the toner images are electrostatically adhered is moved through the pressure point formed between two rollers with the toner image making contact with the heated fused roll to thereby effect heating the toner images inside the pressure point. Typically these fusing systems contain two rolls one of which is the heated fusing roll, the other of which is a compression roll. The fusing roll is typically coated with a compliant material, such as silicone rubber, other surface energy elastomers under tetrafluoroethylene resin sold by E. I. DuPont De Nemour under the trademark TEFLON.

A disadvantage of these melting systems is that since the toner image is made sticky by heat it frequently happens that a part of the image carried on the paper is retained by the heated fusing roll rather than penetrating the surface of the film. paper. This adhesive or sticky toner often sticks to the fuser roller surface and then is deposited on the next pap or on the matching pressure roller. It is toner deposit on the next paper known ccr "off center". Decentering is an undesirable event which lowers the definition and quality of immediate printing as well as the one that contaminates the following toner prints.

To alleviate the problem of toner off-centering it is a common practice to use tonic releasing agents such as silicone oils which are applied to the surface of the fusing roller to act as a toner releasing material. These materials have a relatively low surface energy and are suitable for use in the heated melting roller environment. In practice, a thin layer of silicone oil is applied to the surface of the heated fusing roll to form a gap between the surface of the fusing roll and the image of the toner carrier on the support material, typically the paper. Thus, an easily divided layer of low surface energy presented to the beads passing through the pressure point of the fuser roller and thus prevent the toner from adhering to the surface of the fuser roll.

Numerous systems have been used to deliver fluid and release agent to the fused roll Typically, these prior art systems incorporate texti such as oil or a similar release agent fluid by retaining and delivering the medium. These textiles also serve and play a critical role in the sense that they are used as a fusing cleaning mechanism. With each iteration of the merger rotation, there may be some non-released toner particles that remain on the surface of the merger. This non-released particles are then captured in the interstices of the textile fibers during the termination of the rotation or during the next iteration. ..

The most commonly used textile in current electrostatic or electrophotographic printing machines is here that is known as a needle felt. Suitable wicks are, for example, sold by Andrew Texti Industries Limited or Southern Felt Company Incorporated. Other textiles include those known as non-woven, thermally bonded, hydroentangled non woven fabrics. Most of the textiles used in electrophotographic or electrostatic printing machines are typically made with some aramid fiber content such as those sold by E. I. DuPont Nemours under the trademark NOMEX. Some of these textiles also have some polyester content. Textiles are typically impregnated with a silicone oil such as sold by Dow Corning Corporation. Many of these textiles impregnated with silicone oil are manufactured by BMP Ameri Incorporated, located in Medina, New York, or by BMP Eurct Limited located in Accrington, Lancashire, England.

Even though most of the requirements of the application have been met by these oils impregnated with prior art, some issues still exist with these materials. Under certain conditions these materials can cause a frictional drag that is desirable in the application. This frictional drag can create a slow erosion of the silicone rubber fusing roll, leading to both a decreased life of the fusing roll. Also under certain conditions, these textile materials have shown some degree of looseness or fraying. This loose fraying of fibers is undesirable in the sense that the released fibers can be a source of contamination which can decrease the quality of printing, create mechanical clogging, and act as nucleation sites for an accumulation of accelerated contamination. Accumulation of accelerated contamination can lead to a premature blockage of the delivery of oil from the textile to the fusion roller.

In an effort to overcome some of these issues with prior art materials, textile products have been laminated to polytetrafluoroethylene (PTFE) membranes, such as those available from. L. Gore Company under the brand? GORE-TEX trade. The polytetrafluoroethylene / textile membrane laminate is placed in an electrostatic or electrophotographic printing machine with the polytetrafluoroethylene membrane placed against the fused roll. These polytetrafluoroethylene / text membrane laminates decrease, under certain conditions, the frictional drag forces and decrease the discarded of fiber.

Even when the polytetrafluoroethylene / textile membrane laminate is directed to the discarding of fiber under certain conditions, frictional drag forces are lowered, there is a new set of problems with this products. First, the membranes tend to vary and therefore lose the ability to easily capture contaminants such as the fused toner particles and the paper powder can be made through the interstices of a textile which has not been laminated with a polytetrafluoroethylene membrane. . This is a very recognized problem in the industry. To refer to this matter, the membrane manufacturers have mechanically etched the membrane through a conduit through engraving rollers or have used the polytetrafluoroethylene spray tank on the textured processing surfaces. Some have altered the smooth surface of the polytetrafluoroethylene membrane but have added separate cleaning raspad devices to the electrophotographic electrostatic printing machine. Such cleaning or scraping devices are well known in the industry as doctor's blades. All these cleaning and texturing techniques add cos to what is already a much more expensive material than the textiles that traditionally exist in these applications.

Cost is a second problem that exists with polytetrafluoroethylene / textile membrane laminates. The price of polytetrafluoroethylene / textile membrane laminate systems can be ten times the cost of traditional textiles. The price is very high due to the fact that the polytetrafluoroethylene membrane is a very expensive raw material and costs more than the aramides and polyesters. The cost is also driven by the number of processes involved in producing a polytetrafluoroethylene / textile membrane laminate. These processes include producing a textile, producing a polytetrafluoroethylene membrane by texturizing the membrane surface and then lamination of the membrane to the textile. Again in certain cases, an additional cleaning device such as a doctor's blade is required to meet the requirements of the application. This addition device adds cost as well.

It will therefore be seen that there is a need for textiles that can be used to clean the splicing rolls of electrostatic printing machines, while avoiding the limitations of the prior art. Textile coated fluorocarbon particles for use in electrostatic printing machines, according to the present invention, overcome the limitations of the prior art and are a better signifier over prior art.

SYNTHESIS OF THE INVENTION It is an object of the present invention to provide a textile coated with fluorocarbon particles for use in an electrostatic printing machine.

Another object of the present invention is to provide a textile coated with fluorocarbon particles to clean toner particles out of a fused roll in an electrostatic printing machine.

A further object of the present invention is to provide a textile coated with fluorocarbon particles to remove the toner particles from a melting rod and to deliver the oil as a mechanism for releasing toner in an electrostatic printing machine.

Still another object of the present invention is to provide a textile coated with polytetrafluoroethylene particles, having interstices, for cleaning a fuser roller in an electrostatic printing machine.

As will be discussed in detail in the description of the preferred embodiment which is presented subsequently, the present invention utilizes a textile material which has been coated with fluorocarbon particles to clean toner particles from a fusing roll in an electrostatic printing machine. The textile material may be a woven fabric or one of the generally known nonwoven textiles. The fluorocarbon particles are typically polytetrafluoroethylene, (PTFE) and apply to the textile fabric a way which retains the interstitial characteristics of the textile. In use, the fluorocarbon coated textile fabric acts as an effective fused roll cleaner since it is capable of both removing and retaining the toner particles removed, as well as delivering a toner release agent such as silicone oil. to the merger rodil.

The present invention gains some of the advantages of prior art polytetrafluoroethylene membrane coated fabric while avoiding the disadvantages of a polytetrafluoroethylene membrane coated text. The gains gained are a decreased fiber discard which leads to decreased fiber contamination and lower frictional drag forces, which leads to reduced component wear.

Several disadvantages of the polytetrafluoroethylene membrane coated textiles of the prior art for use in an electrostatic or electrophotographic machine application avoid by the use of the fluorocarbon particle coated textile in an electrophotographic machine application in accordance with the present invention. A textile coated fluorocarbon particles retains the textile interstices to therefore maintain the inherent toner capture of the text and the cleaning capacity, without significantly reducing the oil delivery capacity of the original textile. A text coated with polytetrafluoroethylene membrane from the prior art eliminates the textile interstices from coming into contact with the contaminants and toner for the purpose of cleaning collection. Also, a prior art polytetrafluoroethylene membrane severely restricts the flow of oil through textile. Textiles coated with fluorocarbon particles according to the present invention only moderately lower the flow of oil through the textile. Another advantage of a texti coated with fluorocarbon particles is that their application advantages are achieved at a cost far below the laminates of polytetrafluoroethylene / textile membrane of the prior art. The direct adhesion of fluorocarbon particles avoids some of the cost of the membrane laminates polytetrafluoroethylene / textile through a decreased number of processing steps and through decreased raw material costs.

Textile fabrics coated with fluorocarbon particles for use in electrostatic printing machines in accordance with the present invention overcomes limitations of the prior art. The invention is a substantial ava in art.

BRIEF DESCRIPTION OF THE DRAWINGS Although novel features of textiles coated with fluorocarbon particles for use in electrostatic printing machines according to the present invention will be set forth with particularity in appended claims, a complete complete understanding of the invention can be achieved by referring to the detailed description of the incorporation. preferred, which is subsequently displayed and as illustrated in the accompanying drawings which: Figure 1 is an enlarged and schematic transverse sectional view of an upper surface not covered by a textile fabric according to the prior art; Figure 2 is an enlarged and schematic cross-sectional view of an upper part of a textile sheet to a polytetrafluoroethylene membrane also according to the prior art; Figure 3 is an enlarged and schematic transverse sectional view of a fluorocarbon particle coated textile according to the present invention; Y Figure 4 is an additional schematic and enlarged transverse sectional view of the encircled part of the circle of Figure 3 and showing the coated fiber of fluorocarbon particles.

DETAILED DESCRIPTION OF THE PREFERRED INCORPORATION Referring initially to Figure 1 there can be seen generally at point 10 an amplified cross-sectional view of an uncoated textile fabric of the prior art for use in electrostatic printing machines. The textile fabric 10 is formed by a plurality of fibers 1 which are either woven or non-woven as will be discussed and detailed very soon. These fibers 12 define the interstices spaces 14. The number and size of these interstices 1 will vary with the specific type of textile. It is these interstices 14 which serve as collection areas for the toner particles removed from a fuser roller in the electrostatic printing machine, and which also serve as receptacles for the appropriate release agents, such as the silicone oils that they are transferred to the fusing roller from the textile 10.

As can be seen in Figure 2, which is a display of an arrangement of the prior art, there is generally shown in item 20, a textile coated with a polytetrafluoroethylene (PTFE) membrane. The prior art fabric has the same fibers 12 and interstices 14 as shown in Figure 1. However, these fibers 12 and the interstices are covered by a polytetrafluoroethylene membrane 22. The membrane 22 effectively closes the openings to the interstices 14. between the fiber strands 12. Even though the membrane 22 has the microporous openings 24, they tend to be below one size and are therefore very small to facilitate collection of the toner particles which are typically of the above size. 3 microns These microporous openings are also very restrictive of the flow of the toner release agents, such as the silicone oils that can be retained in the interstices 14 of the polytetrafluoroethylene membrane coated textile of the prior art 20.

Turning now to FIGS. 3 and 4, initially in primary form to FIG. 3, there can generally be seen at point 30 a preferred embodiment of textile coated with fluorocarbon particles for use in an electrostatic printing machine according to the present invention. As can be seen in Figure 3, the text coated with fluorocarbon particles 30 is composed of the fibers 32 having the surface or upper portions 34 which are coated with fluorocarbon particles 36. Co was shown in Figure 3, this Fluorocarbon particle coating 36 is discontinuous across the textile surface of fluorocarbon particle cover 30. It is ensured that access to textile interstices 38 is not impeded. A suitable toner release agent, such as a silicone agent, which is not specifically shown in the drawings, will be capable of flowing from the merger roller interstices 38 of an electrostatic printing machine which is also not specifically shown. Additionally, the openings of the interstices 38 to the surface of the text coated with fluorocarbon particles 30 will suffice both size and number to allow storage of the toner particles removed from the fusilizing rodil by contact between the coated textile and fluorocarbon particles. and the electrostatic printing machine fusing roller.

According to the present invention it provides in one aspect, a coated textile product of fluorocarbon particles weighing in the range of 15 to 60 grams / square meter with the coating of polytetrafluoroethylene particles weighing in the range of 10 to 1 grams / square meter. The textile can be produced by weaving or more typically by needle piercing, thermal uni or hydroentanglement. The polytetrafluoroethylene particles 36 are adhered directly to the textile fibers 34 through either mechanical bonding, chemical bonding or melting. The method of adhesion will depend on the type of fluorocarbon suspension used as well as the processing temperature and the thermal residence time. As discussed previously, these fluorocarbon particles 36 do not require to be a structure continously microscopically to serve the intended purposes.

The base fabric can be produced in a variety of different manners such as weaving, knitting without fabric, thermal bonding without fabric, and fabric hydroentanglement. These processes are well known to those skilled in the art. The fibers 32 of these textiles preferably s aramid, polyester or a mixture of aramid and polyester. The linear density of these fibers 32 varies between 0.5 denier and denier, preferably between 0.5 denier and 7 denier. The area of textiles is typically between 15 and 6000 grams per square meter (gsm). The preferred weight of needle felts ranges from 200 to 6000 grams per square meter; Thermal bonding material varies from 15 to 45 grams per square meter, and the hydroentangled material varies from 15 grams per square meter. The thickness of the textiles typically between 0.040 millimeters and 30 millimeters. The preferred thickness of the needle felts varies from millimeter to 30 millimeters; of thermally bonded materials varies from 0.040 millimeters to 0.300 millimeters; and hydroentangled material varies from 0.040 millimeters to 0.4 millimeters.

The textile coated with fluorocarb particles 30 according to the present invention is produced by applying to the textile fabric one of many commercially available aqueous polytetrafluoroethylene particle suspensions, such as the polytetrafluoroethylene resin sold by DuM De Nemours under the trademark Teflon Polytetrafluoroethylene B ot as Acrylic / Polytetrafluoroethylene sold by Lyons Coatin Incorporated under the name T-31. These suspensions can be applied to textiles and numerous methods. Two suitable methods are: 1) embed the textile inside a bath which contains Teflon suspension of Polytetrafluoroethylene B and 2) process T-31 suspension in a foam which is then spread over the surface of the textile. The amount applied to the textile depends on the user's requirements. Typical quantities vary from 10 to 200 grams per square meter, with the preferred quantity being 10 to 60 grams per square meter. The application of these suspensions is followed by the textile drainage coated through the squeezing and heating of the textile. The heat and pressure of the drain passage effectively fix the polytetrafluoroethylene particles 36 on the surface of the individual fibers 34 of the fabric. It is important to note that the heat required to adequately fix the polytetrafluoroethylene particles to the fibers of the fabric may be well below their melting or sintering temperatures of 323 ° C or 337 ° respectively. The recommended drying temperatures are between 150 ° to 250 ° C, with sufficient thermal residence time to expel the free water.

These textiles coated with fluorocarbon particles 30 are then cut and placed with slits of an adequate size to supply oil to a fusion apparatus in an electrophotographic electrostatic printing machine. These sizes vary from 250 millimeters x 3 millimeters to 50000 millimeters per 1000 millimeters (Longitu x Width). Typically the next step is to impregnate and fabric with a toner release fluid such as silicone oil. Most silicone oil commonly has a viscosity between 50 and 100,000 centistokes s used as the toner release agent.

Textiles coated with fluorocarbon particles 30 are sometimes used in a manner as fusing cleaners or as packing devices in an electrophotographic electrostatic printing machine. The bearing / packing application is particularly advantageous in the areas of photoreceptor / photoreceptor box and lends itself very well to text coated with fluorocarbon particles due to the low friction textile and of relatively low price which is the result of the application of the coating. textile fluorocarbon, as described above.

EXAMPLES: 1) Aramid needle felt was produced c Nomex of 0.9 deniers at a thickness of 2.3 millimeters and with a pe area of 400 grams / square meter. The needle felt f seated with heat at 210 ° C. This needle felt was then coated on the surface with 25 grams per square meter a coating of polytetrafluoroethylene Lyons type T-31 through aeration of T-31 at a blowing rate of 5 a (air to T-31), spreading the T-31 foamed on the top surface of the felt, and then scraping or removing the doctor blade the foam from the fielt surface within one or two seconds of the application initial. The coating was then dried using a convection oven set at 177 ° C for 2 minutes. This textile coated fluorocarbon particles 30 was then cut to a width of 35.5 millimeters and cut to 1143 millimeters long. The coated text 30 was then used in the manner in which an uncoated text would be used to produce a part which between silicone oil to a photocopier fuser roll. The coated textile was spirally adhered to a porous, tube-shaped ceramic core. The required plastics mounting apparatus was adhered to both sides of the ceramic / textile assembly. This textile / ceramic / plastic set f impregnated with 80 grams of silicone oil Dow 200 of 60, 0 centistoques through injection with pressure through d center of a porous ceramic core. The assembly was then oiled with 12 grams of 60.0 centistoke silicone oil from Dow 200 through pressure injection through a multiple drilled onto the surface of the text coated with fluorocarbon particles, generally at point 30 as seen in Figure 3 2) Aramid needle felt was produced c Nomex 2.0 denier at a thickness of 2.3 millimeters and with a pe area of 390 grams / square meter. The construction of needle fielt included a polyester grating as a reinforcement substrate and the final needle felt was seated with heat 210 ° C. This needle felt was then coated on the surface with 16 to 34 grams per square meter of Lyons-type polytetrafluoroethylene T-31 coating through the aeration of T-31 at a blowing rate of 5 to 1 (air at T-31). spreading the T-31 foam on the top surface of the felt, and then scraping or removing with doctor blade the foam from the felt surface within one or two seconds of the initial application.The coating was then dried using a convection oven placed at 177 ° C for 2 minutes This textile coated with fluorocarbon particles 30 f then put ready for cutting into slits, die cutting and oil impregnation to form the final products product as described above.

Textiles coated with fluorocarbon particles made in accordance with the present invention, as recited in examples 1 and 2 above, proved to have oil flow rate much closer to traditionally uncoated textiles than to polytetrafluoroethylene membrane coated textiles. of prior art. A test in which a 10,000 centistoque oil was permeated through various textiles using a 5-inch vacuum pull showed that traditional coated needle felt textiles have an average oil flow rate of 7. grams / minute. A needle felt textile covered with polytetrafluoroethylene membrane exhibited a restricted m flow of 0.2 grams / minute. Needle felts coated with fluorocarbon particles 30 of examples 1 2 exhibited an average oil flow rate of 5 grams / minute. This is clearly much more comparable to the flow rate of oil for the uncoated textiles than what is the flow rate through the polytetrafluoroethylene membrane coated textiles of the prior art.

In accordance with. In the present invention, the fluorocarb particle-coated textile roller assembly produced through Example 1 was installed in a Kodak 2100 series photocopier machine. The average life of the uncoated rolls of the prior art is in the 400,000 a range. 600,000 copies. The life of the uncoated roller is typically terminated through the accumulation of contamination on the roll surface which in turn leads to premature blockage of oil delivery from the fusing fabric. The textile 30 coated with fluorocarbon particles applied to the roller assembly as described in Example 1 lasted 1,700,000 copies and 2,300,000 copies in d tests of separate machines before blocking the delivery of oil through the accumulations of contamination. Thus, the fluorocarbon-coated textile 30 achieved three times more life than the average life of the textile roll not covered by the prior art. This improvement in life can be attributed to the accumulation of contamination over the textile surface. This was achieved without the cost disadvantages of the operation of oil flow of the textile coated polytetrafluoroethylene membrane of the previous ar.

An additional benefit of the fluorocarbon particle coated textiles 30 of the present invention is that the toner particle collection properties are higher than in the laminated textiles of polytetrafluoroethylene membrane of the prior art. Even when collecting toner particles from a textile coated fluorocarbon particles 30 may be somewhat lower than that of uncoated textiles, the advantage of a fiber release which is possessed by the textiles coated with fluorocarbon particles of the present invention exceeds this toner particle collection property slightly reduced when compared to the coated textiles of the prior art such as the textile 10 shown in figure 1.

Although a preferred embodiment of a fluorocarbon-coated textile for use in an electrophotographic electrostatic printing machine in accordance with the present invention has been established and is fully described above, it will be apparent to one skilled in the art that several changes , for example, the particular electrostatic printing machine, the type of photocopying that is being achieved, the type of toner being used similar can be made without departing from the true spirit scope of the present invention which therefore can only be limited by the following claims .

Claims (10)

R E I V I N D I C A C I O N S

1. A textile coated with fluorocarbon particles to be used short a toner cleaner for the fusing system of an electrostatic printing machine said textile coated with fluorocarbon particles has a plurality of fibers, said fibers being at least partially coated with said fluorocarbon particles

2. The textile coated with fluorocarbon particles as claimed in the clause characterized in that it includes a toner release agent.

3. The textile coated with fluorocarbon particles as claimed in the clause characterized in that said textile is an aramid and also where said fluorocarbon particles are directly attached to a surface of said textile.

4. The textile coated with fluorocarbon particles as claimed in clause 1 characterized in that said textile is a polyester.

5. The textile coated with fluorocarbon particles as claimed in clause 1 characterized in that said toner release agent is silicone oil.

6. The textile coated with fluorocarbon particles as claimed in the clause characterized in that said plurality of fibers define interstices and further wherein said fluorocarbon particle coating provides access to said interstices of said surface of said textile.

7. The textile coated with fluorocarbon particles as claimed in the clause characterized in that said fluorocarbon coating polytetrafluoroethylene.

8. The textile coated with fluorocarbon particles as claimed in the clause characterized in that said coating is applied to the textile as a foam.

9. A textile coated with fluorocarbon particles to be used as a gasket in an electrostatic printing machine, said textile coated with a fluorocarbon particle has a plurality of fibers, said fibr being. at least partially coated with said fluorocarbon particles.

10. The textile coated with fluorocarbon particles as claimed in the clause characterized in that said packing is used in a photoreceptor / photoreceptor box area of said electrostatic printing machine. SUMMARY A textile material whose fibers have been coated at least in part with fluorocarbon particles can be used in an electrophotographic printing machine to clean toner particles out of a fuser roll, to supply a toner releasing agent to the fuser roller. The textile material may include woven articles as well as nonwoven felts and the like. The product turns out to have a reduced friction and a decrease in frayed fiber.