JPS594700B2 - Method of treating the surface of a fusing member in an electrostatographic apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates generally to xerographic reproduction methods and apparatus, and more particularly, the present invention relates to xerographic reproduction methods and apparatus, and more particularly, the present invention relates to The present invention relates to fixing modified particulate thermoplastic toners having groups.

Modified thermoplastic toners as referred to herein are toners of the type that have reactive functional groups that interact with the fusing member and are described in more detail below. In the method of xerography, a light image of the original to be reproduced is typically recorded in the form of an electrostatic latent image on a photosensitive member, and this is subsequently recorded by the application of certifiable marking particles, commonly referred to as toner. The latent image is visualized. This visible toner image can be fused directly onto the photosensitive member or transferred to another support such as plain paper and subsequently fused thereto. These toners are of the conventional type or of the modified types described below. In order to permanently fix or fuse the ascertainable toner attachment onto the support member by heat, it is necessary to increase the temperature of the toner material to the point where the components of the toner material coalesce and become tacky. .

This action causes the toner to flow to some extent into the fibers or pores of the support member, or otherwise onto its surface. Thereafter, as the toner material cools, it solidifies and becomes vertically bonded to the support member. In both xerography and electrophotography recording techniques,
The use of thermal energy to fuse toner images onto support members is old and well known. One method of thermally fusing an assayable toner image onto a support is between a pair of opposed roller members, at least one of which is internally heated;
A support carrying a toner image is passed thereon.

During operation of this type of fusing system, the support member to which the toner image is electrostatically adhered passes through a nip formed between the rolls, causing the toner image to contact the fusing roll. The toner image is heated within the nip. By controlling the heat transferred to the toner, substantially no offset of toner particles from the copy sheet to the fuser roll is experienced under normal conditions. This is because the heat applied to the surface of the roller raises the toner's "hot offset temperature" (at which temperature the toner particles in the image area of the toner liquify and cause a fragmentation effect in this molten toner).
This is because it is insufficient to raise the temperature of the roller surface beyond that which causes Fragmentation occurs when the cohesive forces holding the viscous toner mass are less than the adhesive forces, tending to offset it to contact surfaces such as fuser rolls. However, offset of toner particles onto the fuser roll is sometimes caused by insufficient heat application to its surface (i.e., 1
(cold offset): due to defects in the surface properties of the roll; normally the toner particles are held to the copy sheet by electrostatic forces; or due to toner particles insufficiently adhering to the copy sheet; This occurs due to the reactivity of the toner material itself in the case of types having reactive functional groups.

In such cases, toner particles migrate to the surface of the fuser roll and then to the back up roll while no copy paper is in the nip. Additionally, toner particles may be picked up during fusing of duplex copies, or simply from around the reproduction device by fusing and/or back-up rolls.

One device specifically designed to minimize this problem, commonly referred to as ``offsetting'', uses a fusing roll having an outer surface or coating of polytetrafluoroethylene, commonly known as Teflon. A release agent such as silico oil is applied to this fuser roll, and the thickness of this Teflon is on the order of a few mils, and the thickness of this oil is less than 1 micron. . A silicone-based oil (polydimethylsiloxane), which has a relatively low surface energy, is a material suitable for use around the heated fuser roll, where Teflon makes up the outer surface of the fuser roll. It turns out that there is. In practice, a thin layer of silicone oil is applied to the surface of the heated roll to form an interface between the surface and the toner image carried on the support material.

The low surface energy layer thus faces the toner as it passes between the fuser nips, thereby inhibiting toner offset to the fuser roll surface. This system provides only minimal release properties even under optimal conditions and is ineffective when the toner is of a modified reactive type with functional groups thereon. A fuser roll structure of the type described above may be constructed by applying or coating a solid layer of an ahesive material, such as a solid Teflon outer surface, to a rigid core or substrate in any suitable manner. It is manufactured by

The roll structures produced are subject to abrasion and deterioration due to continuous operation at high temperatures and are subject to accidental gouging by stripper fingers commonly used in this system.
ng) be damaged. In many cases, these require replacement of the fuser roll, which is extremely expensive when a large number of machines are involved. Additionally, the polytetrafluoroethylene, along with the silicone oil coating, is thick enough to constitute a poor thermal conductor, requiring longer nip residence and Higher fuser roll temperatures are required.

Further, there is a problem in controlling the surface temperature of the roll due to large temperature fluctuations that occur before and after contact with the image bearing support. In view of the foregoing, the high thermal conductivity and abrasion resistance of bare metal or similar materials would seem desirable for use in fuser roll structures; however, such materials are This has been found to be unsatisfactory for this application.

It is due to the very high surface energy of metals and similar materials that are easily wetted by hot toner materials.
Once wetted by hot toner, it is very difficult, if not impossible, to completely remove the toner from the materials while they are hot. Commonly used release agents such as pure silicone oil and mineral oil have been attempted in combination with various metals and other high surface energy materials with relatively little or no success. US Patent 7f6.38
10776, the offset of the toner relative to the heat fuser roll is an immiscible dispersion of a high viscosity, low surface tension component, such as a lead reject or aluminum stearate or behenate, and a low viscosity, low surface tension component, such as a silicone oil. This has been reported to be inhibited by coating the fuser roll with an anti-adhesive layer.

However, at least two component systems with immiscible components must be applied and/or mixed to prevent hot offset. This in turn creates redundant manufacturing, handling and application problems. Furthermore, these systems are ineffective in preventing hot-offsetting of reactively modified toners having functional groups. OBJECTS OF THE INVENTION It is therefore a principal object of the present invention to provide a new and improved release agent, fusing method and apparatus for use in fusing toners when the toners are of a modified type having functional groups thereon. Our goal is to provide the following.

Another object of the invention is that when a functionalized reactive toner is used to develop an electroscopic image, the fusing member is self-repairing and therefore continuous. It is an object of the present invention to provide a fusing method, apparatus, and release agent for use in a photocopying apparatus and method having a reproducible surface. Another object of the present invention is a fusing method in which the modified toner is expelled from the exposed surface of the fusing member by the action of a release agent of single component or multiple miscible components on the surface of the fusing member. and equipment.

Yet another object of the invention is that the release agent is solid or liquid at room temperature and remains liquid during fusing of the toner image to the substrate.
An object of the present invention is to provide a fusing method and apparatus using a release agent for modified toner containing a functional group.

Still another object of the invention is that an interfacial barrier is formed between the fusing member surface and a release layer applied thereto, which layer may be provided from a single component system or a multiple miscible component system; An object of the present invention is to provide a fusing method, an apparatus, and a release agent that prevent modified toner from contacting the surface of a fusing member. Other objects and advantages of the invention will become apparent when read in conjunction with the accompanying drawings and the following description.

SUMMARY OF THE INVENTION The foregoing objects of the present invention are achieved by applying a polyorganosiloxane having carboxy functionality to a heat-sealing member in an electrostatographic reproduction apparatus.

The carboxy functional groups of the polymeric polyorganosiloxane fluid can interact with the fusing member surface to form a thermally stable barrier to the modified toner, referred to herein as the interfacial layer, which provides a thin coating that adheres strongly to metallic glass or other surface materials and has release properties for modified toners used in electrostatic printing. This functional carboxyl group is generally known as a chemically reactive group. The carboxy-functional polyorganosiloxane fluid can be applied to the surface of the fusing member at a thickness ranging from submicrons to several microns to constitute a minimal barrier to heat transfer. By using the release agent and method of the present invention, a fusing member is provided that essentially has a bare surface surrounded only by a microscopic layer of material that prevents toner from contacting the surface. Ru. Although this mechanism is not completely understood, when a polyorganosiloxane with carboxyl functional groups is applied to the surface of a fusing device, the metal or glass surface of the fusing member and the polyorganosiloxane with carboxyl functional groups interaction (chemical reaction, coordination complex, hydrogen bonding or other mechanism) between the metal, glass or other material of the fusing member and the functional polyorganosiloxane. It has been found that an interfacial barrier layer of material is formed intermediate the metal or glass or other substrate of the fuser member and the fuser member covering the polyorganosiloxane fluid.

This outer layer is referred to as the unreacted release layer, or commonly referred to as the release layer. However, the coating formed has a greater affinity for the fusing substrate material than the modified toner and thus prevents the modified electroscopic thermoplastic toner with functional groups from contacting the core, while the release coating It has been found that it imparts a cohesive force to the material that is less than the adhesive force between the heated toner and the substrate to which it is applied or the cohesive force of the modified toner. It has been found that these coatings not only release to the modified toner, but are also continuously reproducible and self-healing when the modified toner is used to develop electrostatic images. That is, if this coating is exerted, for example, by non-uniform pressure exerted by a blade used to meter the core Hellerize material, or by a finger used to strip the toner image support from a fuser roll structure. The thermostable coating will regenerate itself if damaged by undue force. Other polyorganofunctional siloxanes (polyalkylsiloxanes with functional groups) do not release for modified toners other than the functional release materials described and claimed in U.S. patent applications filed on the same day and assigned to the same assignee. In view of the facts, polyorganosiloxanes having carboxy functionality have unexpectedly been found to be useful as release agents for modified toners having functional or reactive groups as described below. Modified toners with functional groups are also expected to be excluded from damaged or worn areas that interrupt the coating on the heat-sealable member when carboxy-functional polyorganosiloxanes are used in accordance with the present invention. It turned out outside. The softened or tacky modified toner was substantially removed by a functional polyorganosiloxane fluid having chemically reactive functional groups, and the fluid was discontinued. Repair damaged or worn areas. This action substantially eliminates the offset problems common in prior art devices and methods. In describing the coating material or release fluid of the present invention, the term carboxy-functional polyorganosiloxane fluid is also used to refer to the state that this polymeric material assumes at operating temperatures. Thus, polyorganosiloxane materials having chemically reactive carboxy groups are solid or liquid at ambient temperatures and fluid at operating temperatures. The term "polymer" is defined as having a chemically reactive functional carboxy group bonded thereto capable of interacting with the fusing member to form a barrier to the modified toner, and which has a chemically reactive functional carboxy group capable of interacting with the fusing member to form a barrier to the modified toner. It refers to two or more monomer units as a backbone having a surface energy smaller than the surface energy. In the method of the present invention, it is important that the polyorganosiloxane fluid contains chemically reactive functional carboxy groups that interact with the fusing member to form a thermally stable interfacial barrier to the modified toner.

The carboxy-functional polyorganosiloxane fluid also eliminates the functional group-containing modified electroscopic resin toner when it is coated onto a fusing member, thereby promoting adhesion of the toner to the surface of the fusing member or to the fluid layer itself. Prevention is also important. As used herein, "toner repellent" means that the carboxy-functional polyorganosiloxane is capable of preventing modified toner from contacting the fusing member surface, and that surface is exposed to or exposed to toner. This means that the siloxane is more reactive with the material on the fuser member surface than the modified toner, such that it displaces or eliminates the modified toner from the surface of the fuser member even when in contact with the fuser member. Preferred Embodiments Carboxy-functional polyorganosiloxane fluids capable of eliminating modified toners having functional groups are operable in accordance with the present invention only when appropriate carboxy functionality is present in the fluid.

``The polymeric fluid must also have a suitable release action on the modified toner and form an interfacial barrier between the metal, glass or other material of the fusing member and the outer layer of the fluid release material. must be able to do so. The present invention is characterized by the above-mentioned properties and has a built-in
1n) Contains polyorganosiloxanes with carboxy functionality.

The term 1-specific "゜carboxy-functionality" refers to any polyorganosiloxane material characterized by a carboxy functional group (-COOH). This polyorganosiloxane is a siloxane containing alternating silicon and oxygen atoms in the main chain. Because of the main chain structure, they are commonly referred to as inorganic polymers.The polysiloxane chains themselves (-Si-0-Si-0-)n are typically inorganic in nature; is thermally and chemically stable in nature. However, it can also be considered organic in nature because of the hydrocarbon spacer groups and side chains that are part of this molecule and are attached to the siloxane backbone. A typical carboxy-functional polysiloxane backbone has the general formula (Formula R represents a ``spacer'' group pendant from the polymer backbone and CO
OH is a carboxy functional group).

In a preferred embodiment, R is an alkyl moiety having about 1-8 carbon atoms, typically a propyl group (-CH2-CH2-C
H2-).

For a typical polymer with a 1 mole % functionality content, there is 1 a part for every 99 b parts.

When the carboxy functional group content is 2 mol%, 98
There are an average of 2 a parts for every b part. The R spacer groups may all be the same, for example methyl, ethyl or propyl, or they may be a mixture of alkyl groups, such as a mixture of propyl and butyl, or a mixture of ethyl and propyl, etc. good. Furthermore, this R spacer group is a straight chain or a branched chain. A typical molecule represented by the above general formula has a methyl group substituted with a Si atom at a non-spacer group position. However, these non-spacer group positions may also carry general alkyl groups, typically of 1 to 6 carbon atoms, and mixtures thereof. Other groups may be substituted at these positions by those skilled in the art as long as the substituents do not interfere with the carboxy functionality represented by the general formula -COOH. The R-COO groups may be randomly arranged in the molecule to provide important functionality to the release agents, methods, and devices of the present invention.

Otherwise, or on top of the carboxy functionality (-CO
OH) may be placed on the spacer group (R) at the terminal position of the molecule; ie the molecule may be End-Capped 1 by a carboxy function. Release agents, carboxy-functional release agents, polymeric fluids, carboxy-functional polyalkylsiloxanes and carboxy-functional polydialkylsiloxanes are used interchangeably herein, and polyorganofunctional siloxanes having carboxy-functional groups are used interchangeably herein. means the foregoing including. A polyorganosiloxane having chemically reactive functional groups to enable suitable release of thermoplastic toner with improved offset when bare fuser rolls are used in the method and apparatus of the present invention. The release agent must have the following properties either before, during or after application to the fusing member surface.

The carboxy-functional polydialkylsiloxane release agents are preferably non-volatile; that is, they do not contain volatile fumes and vapors that permeate into the surrounding atmosphere and thereby cause deposits on surrounding parts in the reproduction apparatus, or that are toxic in the environment. shall not result in excessive levels of fume.
The carpoxy-functional polyalkylsiloxane releasing agent on the fusing member must be thermally stable; that is, the fluid will gel at operating temperatures for a reasonable period of time (e.g., at least about 200 hours at operating temperatures). Do not form or disintegrate. This depends on the specific requirements of the machine and machine application. The carboxy-functional polyalkylsiloxane fluid preferably is non-corrosive to mechanical parts and paper, and should be non-reactive, i.e., inert, to the toner used to develop the electrostatic latent image. . The carboxy-functional polydialkylsiloxane fluid must present a low energy surface to the thermally fused toner, i.e. it must be difficult to adhere to, and this surface energy must be must be smaller than the surface energy of the toner.
For example, when a toner is used that typically has a room temperature surface energy of about 28-36 dynes/(1-J moV1), the fluid must have a surface energy less than the surface energy of the toner. The interfacial layer is preferably is impermeable to modified toner; that is, the modified electroscopic thermoplastic resin toner, which has been softened by the action of the fusing member, penetrates into the undamaged interfacial barrier layer, so that the surface of the fusing member becomes There must be no exposure to the modified toner particles trapped in the overlying layer. The barrier-forming interfacial layer between the fuser member surface and the outer release layer should preferably be on the order of 10 microns or less applicable to the fuser member, and the barrier-forming interfacial layer between the fuser member surface and the outer release layer should be free of non-volatile fluids even at the operating temperature of the device. Preferably, it is insoluble in the release layer.The carboxy-functional polyorganosiloxane preferably has a viscosity of about 2 at 320'F.
Higher than 0 centipoise. Generally, the method of using the carboxy-functional polyalkylsiloxane release agents of the present invention allows the coating to be applied continuously to the surface of the fusing member, in which case the coating is considered self-renewing. .

The carboxy-functional polyalkylsiloxane fluid is applied to the fusing member by any standard or conventional method or equipment known to those skilled in the art, and the methods of application include brushing, spraying, metering from a reservoir, carboxy-functional polyalkyl siloxane fluids, etc. application from a wiper blade or wiper containing a polyalkylsiloxane with groups, application from a suitable reservoir,
Including application by roll or wicking, application by tucking, etc. Generally, those skilled in the art will appreciate that functional group-containing modified (reactive) thermoplastic toner imagewise applied onto a support must be heated or fused to permanently fix the imagewise colored material on the support. The present invention can be used in fusing assemblies for reproduction machines that do not require a copying machine. Carboxy-functional polydialkylsiloxane release materials may also be applied in solid form, which becomes fluid at operating temperatures: for example, by rubbing a suitable carboxy-functionalized polymer block onto a heat-sealable member. A polymeric film may be applied over the fusing member. The polymerizing agent release agent may be applied with a cutting agent or diluent that is miscible, ie, as two or more miscible components. An example of this is a mixture of polydimethylsiloxanes having a functional carboxy group attached to a propyl spacer group, mixed with a polydimethylsiloxane (silicone oil) that is miscible and acts as a diluent. Typical formulations include 50/50 and 25/75 carboxy functional release material to silicone oil. The carboxy-functional release agents of the present invention can also be applied as a single component to provide both an interfacial barrier and a release surface. In applying a carboxy-functional release fluid capable of displacing electroscopic thermoplastic toner to the surface of the fusing member,
(This polymeric fluid contains chemically reactive carboxy functional groups that can interact with the fusing member surface to form a thermally stable interfacial barrier to the modified toner). This fluid is small in order to not only release the heated modified thermoplastic toner, but also to provide the fusing member with an amount of surface that prevents the modified thermoplastic toner from contacting the surface of the fusing member. It must be applied in an amount sufficient to coat the surface with a continuous low surface energy film.

Generally, in accordance with the purposes of the present invention, an amount sufficient to coat a surface will maintain a fluid thickness in the submicron to micron range (preferably about 0.5 to about 10 microns in thickness). ) must be the amount. Thus, essentially the layer of polymeric fluid on the surface of the fusing member is so slight that there is essentially a bare fusing member. The method of applying this layer or coating of chemically reactive carboxy-functionalized polymeric fluid to the fusing member surface may be intermittent, but may include continuous application of the fluid onto the heated fusing member. It is generally preferred to maintain a coating of the polymeric fluid thereon and the product or products formed by its interaction with the material of the fusing member. During operation of any automatic electrostatographic apparatus, when the support is of the type that absorbs fluid and attaches a force slope, a heat-sealing member is used to replenish the fluid carried away by the support. It is generally preferred to apply a fraction of the fluid in succession, generally in fractions of microliters per copy. However, from the surface of the fusion member,
In embodiments where there is little or no loss of polymer fluid with chemically reactive functional groups, continuous application of the fluid is not necessary and it is preferred to use application techniques that simply apply the fluid intermittently to the surface. . In order to be operable in accordance with the present invention, polymeric fluids having chemically reactive carboxy functional groups which can be applied to the fusing member and exclude potash electroscopic thermoplastic toners may be used as described above. must not be capable of curing to the extent of forming a solid or gel during periods of stress at operating temperatures. This commensurate time is dependent on the copier capacity, and the proportion time for high capacity copiers is at least about 200 hours, whereas the proportion time for low capacity copiers is preferably greater than 200 hours; and 1000 to 2000 hours or more. Thus, if the polymeric fluid applied to the fusing member is of a type that rapidly forms a solid or gel at the operating temperature of the device (generally about 250-400'F), it is suitable for use in accordance with the present invention. It cannot be used. Generally, the method of the present invention is used to fuse a modified electroscopic thermoplastic toner image to a support and includes the step of forming a coating or layer on a heat fusing member of an electrostatographic apparatus; This coating is a barrier to the modified (reactive) electroscopic thermoplastic toner and products resulting from the interaction of the fusing member with the polymeric fluid having chemically active carboxy functional groups thereon. The polymer is fluid at the temperature of the fusing member and acts as a release coating for the electroscopic thermoplastic toner.

The toner image on the support is contacted with a heat fusing member for a time sufficient to soften the modified (reactive) electroscopic thermoplastic toner, and the softened toner is then cooled. left alone. The toner barrier coating and fluid toner release coating are preferably on the order of about 0.5 microns in thickness. The thickness of the barrier coating and the release layer are such that the barrier coating and the release layer do not impede heat transfer from the inner core of the fusing member to the thermoplastic resin toner, which performs the fusing onto the support, and that the thickness of the barrier coating and the release layer are such that the barrier coating and the release layer do not impede heat transfer from the inner core of the fusing member that performs fusing onto the support to the thermoplastic resin toner. The material is tackified to prevent hot-offsetting on the member (i.e., to prevent the toner retained on the heat-sealing member from being transferred to the next support that contacts the heat-sealing member). There is a limit to the extent to which there is a sufficient film of release material on the surface of the fusing member to prevent retention of molten modified thermoplastic toner by the surface of the fusing member. The modified electroscopic thermoplastic resin toner forming the toner image numbered 14 in FIG. 1 comprises, for example, a thermoplastic resin in addition to colorants such as dyes and/or pigments. Examples of conventional pigments are carbon black and furnace black. The developer material may also contain cleaning materials and plasticizers depending on the desired formulation. According to the present invention, these toners are of one type, ie reactive (functional) toners rather than non-reactive conventional toners well known to those skilled in the art.

Non-reactive toners do not have functional groups that can interact with the fusing member material. Reactive toner materials are chemically reactive and generally have functional groups that can interact with the fusing member material. release agents and those described in commonly assigned U.S. patent applications.However, according to the present invention, carboxy-functional polyalkylsiloxanes are superior to these toners in the tackified state. It has been found that this release agent is capable of removing and eliminating this reactive toner from the surface of the fusing member.Furthermore, the release of modified toners with carboxy-functional polyalkylsiloxanes was disclosed on the same day as the present application. For purposes of distinction, examples of non-reactive or non-functional toners include copolymer mixtures of styrene or ethyl toner as described in U.S. Pat. No. 3,079,342. 10-40% (by weight) of one or more methacrylate esters selected from the group consisting of , propyl, and butyl methacrylate and a styrene monologue, which document is incorporated herein by reference.

Typical toner materials are copal rubber, sandarax rubber,
Includes rosin, asphalt, pylsonite, phenol formaldehyde resin, rosin modified phenol formaldehyde resin, methacrylic resin, polystyrene resin, polypropylene resin, epoxy resin, polyethylene resin and mixtures thereof. Among other patents describing non-reactive thermoplastic electroscopic toner compositions are Copl.
U.S. Patent No. 2,659,670 for Landrigan (L
andrigan) U.S. Patent No. 2754408: Insalaco (Inki 1aco) U.S. Patent F630793
42: Carlson US Patent Rei
ssue7F6.25136 and line flank (Rh
There is a US Patent No. 2,788,288 by Einfrank et al. An example of a modified reactive or functional toner that is unexpectedly released from a heat-sealable member having a film of a carboxy-functional polyalkyl siloxane thereon in accordance with the present invention is a diol consisting of a dicarboxylic acid and a diphenol. It is a polymer esterification product of

A typical reactive or functional toner is Palermici (Pal
ermiti and Chatterji, US Pat. No. 3,590,000, which is incorporated by reference. What is claimed therein is a solid xerographic developer material comprising particles comprising a finely divided toner material having a particle size range of up to about 30 microns and a melting point of at least about 110 m below; a colorant selected from the group consisting of pigments, dyes and mixtures thereof; and a resin consisting essentially of a polymeric esterification product of a dicarboxylic acid and a diol consisting of a diphenol; and the weight of said toner material. On the basis of the,
Approximately 0. The outer surface of the particles contains at least about 20% by weight of a solid, stable, hydrophobic fatty acid metal salt that can be used. This type of modified reactive toner is described herein as a functionalized modified thermoplastic toner. These functional groups are of the type that react with the surface of the fusing member. As used herein, modified toner, modified electroscopic thermoplastic material (toner), functional toner, reactive toner, modified toner having functional groups are considered interchangeable terms. In carboxy-functional polyalkylsiloxanes, this functionality present in the polymer release fluid containing chemically reactive carboxy functionality (-COOH) is used to eliminate modified electroscopic thermoplastic toners. The concentration or amount of groups is generally 2.0% per molecule.
A concentration of carboxy groups of 0 or less is preferred.

Depending on the mode of fluid application, higher carboxy functionality can be present in polymer fluids containing chemically reactive carboxy groups, such as polyalkylsiloxanes containing up to 10 carboxy groups or more per molecule. Fluids can also be used. As explained above, the polymer may be diluted or cut by the addition of a miscible non-functional material prior to or during application to the fusing member. Although concentrations of functional groups in the polymer fluid of 10 mole percent or greater may be used in accordance with the present invention, there is generally no advantage to using concentrations of 10 mole percent or greater.

Concentrations as low as about 0.2 carboxy groups per molecule have yielded satisfactory results. In order to treat the surface of a heat-fusing member in an electrostatographic apparatus by applying at least one polymeric fluid containing chemically reactive carboxylic groups, one skilled in the art will appreciate that the polymeric fluid is The concentration of functionality can be adjusted to provide optimal release and fusing latitude. A suitable or optimal concentration of carboxy functionality in the polymer fluid can be determined by performing simple tests. Since the fusing latitude and release properties of the polymer fluid vary with the composition of the fusing member, this test must be performed on the same base metal used for the fusing member surface. The concentration of carboxy groups on the polymer fluid can be adjusted to provide optimal fusing latitude and release according to the speed at which the modified thermoplastic toner is to be fused. This test can be performed on a small heated roll fuser having the desired metal, glass or other suitable surface with a suitable backup or pressure roll. The speed and nip pressure can be adjusted as desired and the test material can be metered onto the fuser roll member by a metering device such as a blade from a suitable device, such as a sump system. A suitable thermocouple controls the temperature and measures the surface temperature on the fusing member. The minimum fusing temperature and hot offset temperature are determined for a measured amount or concentration of chemically reactive carboxy functional groups. The unfused modified thermoplastic toner on the support is fed into the fusing member nip and the latitude test and release characteristics are measured, including the thermal stability of the material. The various metals were tested simply by changing the fuser roll members in the test apparatus, and the various polymeric release agents (concentration, amount, or location of chemically reactive carboxy functional groups) were tested. by replacing the solid or fluid material in the reservoir or by replacing the solid or fluid material with chemically reactive carboxy functional groups in any other type of applicator device. can be measured. The surface to which the polymeric material (which must be solid but fluid at the operating temperature) is applied has chemically reactive carboxy functional groups to prevent the interaction between the polymeric fluid and the surface of the fusing member. To ensure proper formation of the resulting interfacial layer, it must be heated.

The interfacial layer is thus heated and remains as a barrier layer on the surface of the fusing member. Generally, the unreacted or virgin release agent when it is applied to the fusing member is heated to the temperature of the fusing roll; however, when heat transfer occurs, i.e., the heat transfers the thermoplastic toner from the fusing member The release fluid is somewhat cooler than the rolls during operation of the device when it is transferred to the support to perform the fusing process. This temperature can be adjusted by those skilled in the art according to the particular type of modified thermoplastic toner, according to the speed of the equipment, and according to any other parameters known to those skilled in the art. The molecular weight of the polyalkylsiloxane fluid containing chemically reactive carboxy functionality must be high enough that the fluid is not very volatile.

It has been found that molecular weights on the order of 5,000 are satisfactory, and preferred molecular weights are about 10,000 to 15,000 and above.

If the molecular weight of the polymer fluid is too low, volatile materials are generated that are corrosive or irritating, harmful, or aggressive. If the molecular weight of the polymer material is too high,
The coating thickness is difficult to control because it is difficult to meter, and the fluid becomes sticky to the resinous toner. Thus, when carboxy-functional polyalkylsiloxanes are used to treat the surface of the fusing member of an electrostatographic device, volatile materials are not released: and effective metering is possible. , the molecular weight of the release material should be selected. By observing the behavior of this particular fluid during the tests outlined above to determine the concentration of carboxy functionality required in the fluid, the preferred or optimal molecular weight can be determined without the need for extra experimentation. can be selected. When the low molecular weight fraction is removed from an otherwise suitable fluid, a suitable polymer fluid containing chemically reactive carboxy functional groups and having a molecular weight within an optimum range is obtained. Release defects in polymer fluids with chemically reactive carboxy functionality are associated with image splitting, when the modified toner becomes softened and sufficiently tacky to adhere to the surface of the fuser roll. It creates a partial or ghost image on the next sheet, creating what is called an offset image.

Therefore, the release properties of a particular polymeric fluid applied to the fuser member surface are a function of the offset image, and as the temperature of the fuser member increases until hot offset occurs, release characteristics become better. Further, it is a temperature from the temperature at which the modified thermoplastic resin toner begins to fuse to the point at which hot offset occurs;
Also, the fusion latitude, which is a function of the release properties of polyalkylsiloxane fluids containing chemically reactive carboxy functional groups, is greater. This fusing latitude, ie, the temperature range that includes the temperature at which the fusing member is operable and the modified thermoplastic toner begins to fuse to the temperature at which hot offset begins, is also known as the fusing window of the fusing member. There is. This fusion latitude is unexpectedly made possible by the use of polyalkylsiloxane fluids having chemically reactive carboxy functionality. One means of fusing the modified toner material to the support is fusing consisting of a heated roll structure comprising a hollow cylinder or core with suitable heating elements disposed in a hollow member coextensive with the cylinder. It is an assembly.

This heating element raises the surface temperature of the cylinder to typically 250-
It comprises any suitable type of heater, such as a quartz lamp, to raise the operating temperature to 400'F. This cylinder must be made of a suitable material capable of achieving the objectives of the invention; i.e., it must not only transfer heat to the surface to provide the temperature required to fuse the toner particles, but also the carboxylic In order to interact with the polyalkylsiloxane release agent having a functional group and prevent the modified toner particles from coming into contact with the surface of the fusing member, an interfacial layer, i.e., an interfacial layer for the modified toner, is provided between the release layer and the surface of the bare fusing member. It must be manufactured from a material capable of forming a product that becomes a barrier layer. Typical fusing members are anodized aluminum and its alloys, steel, stainless steel, nickel and its alloys, nickel-plated copper, copper, glass, lead, cadmium, etc., and combinations of the foregoing.

The cylinder may also be coated with any suitable material which is non-reactive with the release agent as long as the surface of the cylinder is coated with a material capable of achieving the objects of the invention, especially a polymeric material having carboxy functional groups that is capable of interacting with the release fluid. It can be manufactured from various materials. The surface temperature of the fusing member can be adjusted by means known to those skilled in the art, for example as described in US Pat. No. 2,327,096. Generally, the fuser assembly also includes a backing, such as a roll or belt structure, that cooperates with the fuser roll structure to form a nip through which the copy paper or support passes so that the toner image is in contact with the fuser roll structure. Contains an uproll member. The back-up member may include any suitable structure, such as a steel cylinder or a rigid steel core with an elastomeric layer thereon, or as needed between the fusing member and the support carrying the developed latent image. A suitable belt that provides contact. The dimensions of the fuser member and backup member are determined by those skilled in the art and are generally dictated by the requirements of the particular reproduction equipment in which the fuser assembly will be used, which dimensions will depend on process speed and other parameters of the machine. are doing. Means may be provided for applying a loading force to the fusing assembly in a conventional manner to create a nip pressure on the order of about 15 to about 150 psi on average. At least one polyorganosiloxane fluid capable of excluding modified electroscopic thermoplastic toner is applied to the fusing member surface.

The siloxane fluid contains chemically reactive functional carboxy groups that can interact with the fusing member surface to form a thermally stable layer, and the modified thermoplastic toner contacts the fusing member surface. sufficient to coat the surface with at least a continuous, low surface energy film of the fluid to prevent the melting and release of the modified thermoplastic toner heated by the fusing member. Applied in quantity. A fusing member treated according to the method of the present invention is exemplified by the fusing assembly shown in FIG. The numeral 1 in FIG. 1 indicates the fusing assembly, which includes a heated roll structure or solid substrate 2, a back up roll 8, and a reservoir 20. The heated roll structure or solid structure 2 comprises a hollow cylinder or core 4 with a suitable heating element 6 arranged in a hollow part coextensive with the cylinder. Backup roll 8 cooperates with roll structure or solid substrate 2 to form a nip through which copy paper or support 12 passes such that toner image 14 contacts fuser roll or solid substrate 2.

As shown in FIG. 1, the backup roll 8 has a rigid steel core 16 with a surface or layer 18 thereon. The hollow cylinder or core 4, manufactured from metals such as anodized aluminum, aluminum and its alloys, steel, nickel and its alloys, copper, etc., as mentioned above, has a surface made of a relatively high surface energy material. , and consequently the toner materials 14 that come into contact with this surface when they are heated readily wet the surface. Therefore, the polymeric release agent 2 is capable of excluding modified reactive (functionalized) electroscopic thermoplastic toners when said material is in a fluid state.
A reservoir 20 is provided in accordance with the embodiment of FIG. 1 for containing a polymeric release material which interacts with the fusing member surface to form a thermally stable interfacial layer thereon when in the fluid state. Contains chemically reactive carboxy functional groups that can be formed. The polymeric release material 22 may be solid or liquid at room temperature, but must be a relatively low viscosity fluid at the operating temperature of the fuser roll structure or solid substrate 2. The release material 22 in the reservoir 20 must have inherent chemically reactive carboxy functional groups that can interact with the surface material 2 found on the hollow cylinder or core 4. In embodiments of the invention, the chemically reactive group of polyorganosiloxane release material 22 in reservoir 20 is carboxy (-COOH). In the embodiment shown in FIG. 1 for applying a polymeric release material 22 to a solid substrate 2, a metering blade, preferably of conventional non-swelling rubber, is provided with its edge 26 in contact with the solid substrate 2 of the fuser roll. The reservoir 20 is attached by conventional equipment to serve as a metering device for applying release material 22 having chemically reactive groups to the fuser roll in a liquid or fluid state.

By using this metering blade, a layer of polymer release fluid 22 can be applied to the surface or substrate 2 in a controlled thickness ranging from submicron thickness to several micron thickness. Thus, metering device 2
4, a release fluid with a thickness of 0.1-0.5 microns or more can be applied to the substrate 2. In the illustrated embodiment, a pair of end seals 28, for example of sponge rubber, are provided to contain the release material in the reservoir 20.
One or more stripper fingers 30 may be provided to ensure removal of the support from the substrate 2. In one preferred embodiment, the modified thermoplastic toner is fused to paper, but the modified thermoplastic toner can also be fused to other supports, such as polymeric films, by the fusing member and method of the present invention. Can be fused. The only limitations are that the chemically reactive carboxylic polymer fluid does not adversely affect the modified toner bearing support and does not destroy or alter the color properties of the modified thermoplastic toner. The above embodiment of FIG. 1 coats a surface with at least a continuous, low surface energy film of fluid to provide a fusing member with a surface that releases modified thermoplastic toner heated by the fusing member. Suitable for applying a layer of polymeric release material containing chemically reactive carboxy functional groups capable of interacting with the fusing member surface to form a thermally stable interfacial barrier layer in an amount sufficient to It is just one of many devices.

Other devices for applying a polymeric release fluid with carboxy functional groups that have poor adhesion to modified electroscopic thermoplastic toners and interact with the solid surface of the fusing member release fluid onto the fusing member surface. Apparatus for spraying a layer of fluid, a pad or sponge-like material for padding a coating of a polymeric release fluid having chemically reactive carboxy functional groups on the surface of a fusing member, chemically reactive carboxy functional groups a device for extruding a microfilm of polymeric release material having chemically reactive carboxy functional groups on the fusing member to provide a film or layer of polymeric release material having chemically reactive carboxy functional groups; a brush having fibers or bristles made of a polymeric release material having carboxyl functional groups that are reactive to the bristles or a polymeric release fluid having chemically reactive carboxy functional groups on the surface of the bristles or the brush material; Includes bristles, fluid-dipped rolls or wicks, etc. A fusing member for an electrostatographic apparatus resulting from a method of treating the surface of the heat fusing member with at least one polymeric fluid capable of eliminating modified electroscopic thermoplastic toner is shown in FIG. .

The fuser member shown in FIG. 2 has been enlarged several times over the member shown in FIG. 1 to show the thin layers on the fuser member surface.
In FIG. 2 the heated roll structure or solid substrate is designated by the number 2. The fluid release layer is designated by the number 64 and the surface layer is designated by the number 60. Thus, the solid substrate 2 has poor adhesion to the modified reactive electroscopic thermoplastic resin toner;
and a polyorganofunctional siloxane fluid 64 having chemically reactive carboxy functional groups that interacts with the solid substrate 2 and a modified electroscopic thermoplastic toner (not shown).
an interfacial layer 60 that unexpectedly prevents contact with the solid substrate 2 (this interfacial layer 60 is formed by the interaction of the solid substrate 2 with the chemically reactive carboxy functional groups of the polyorganofunctional siloxane fluid release layer). A fusing member is described that has a In one preferred embodiment, the second
The solid substrate 2 in the figure consists of a metal capable of forming oxides, and in a further preferred embodiment this solid substrate 2 consists of iron, copper,
It may be selected from the group consisting of aluminum, titanium, lead, silver, nickel and cadmium and oxide-forming alloys thereof. The solid substrate 2 may also be composed of glass. In accordance with the present invention, the solid substrate 2 of FIG. 2 is an oxide-containing or forming material and the polymeric fluid 64 is of the carboxy functional type, and the modified electroscopic thermoplastic toner is disposed therein. When applied and softened, the release layer 64 and interfacial layer 60 are discontinuous, and the action of the carboxy functionality of the polyorganofunctional siloxane fluid 64 applied thereon also causes the surface of the substrate 2 to be exposed to toner. It has been unexpectedly found that the modified electroscopic thermoplastic toner is excluded from the solid substrate 2 by the method.

Discontinuities in the release layer 64 and the interface layer 60 can be created by, for example, scraping the surface with a stripper finger.
This can be caused by other abrasive forces that rub or abrade the layer coated on the solid substrate 2 by means of a thermistor device regulating the temperature at the surface. Thus, when the modifying reactive electroscopic thermoplastic toner is applied to the surface interrupted by this force, the modifying reactive electroscopic thermoplastic toner is applied by the action of the polymeric release layer material as it is applied to the fusing member. It was unexpectedly found that the resin toner was excluded from the solid substrate 2. Although the details of this mechanism are not completely understood, the chemically reactive carboxy-functionalized polyalkylsiloxane release fluid actually competes with the modified reactive electroscopic thermoplastic toner for the surface of substrate 2. and because the release material with chemically reactive carboxylic groups is more reactive to the solid substrate surface 2 than the modified reactive electroscopic resin toner, the release material 64 is Interfacial layer 6 due to interaction with surface 2
It is conceivable to actually eliminate the modified electroscopic thermoplastic toner from the substrate 2 by reforming the 0. Thus, when using a modified electroscopic thermoplastic toner that has functional groups and is considered reactive, the release layer fluid, which has carboxy functional groups, is acted upon and softened on the surface of the fuser roll. It has been found that the modified electroscopic thermoplastic toner actually eliminates the discontinuities that occur thereby inhibiting material offset and image ghosting. The examples below further define and describe exemplary materials for treating the surface of a heat fusing member in an electrostatographic apparatus with a polyorganofunctional siloxane fluid that can eliminate modified electroscopic thermoplastic toners. However, and by comparison, this fluid contains chemically reactive carboxy functional groups that can interact with the fusing member surface to form a thermally stable interfacial layer thereon.

Parts and percentages are by weight unless otherwise specified. Molecular weights are number average unless otherwise specified. The examples also illustrate various preferred embodiments of the invention. Unless otherwise specified, polyalkylsiloxane fluids containing chemically reactive carboxy functional groups were applied to the fusing member surface by the apparatus described above and shown in FIG. When measuring the effectiveness of polyalkylsiloxane fluids containing chemically reactive carboxy functional groups, an electrostatic latent image is formed on a conventional recording surface in a conventional electrostatographic machine, and this electrostatic The latent image is incorporated herein by reference in US Pat. No. 3,590,000.
A coloring agent, a solid, stable, heat-fusible reactive product consisting of a polymeric esterification product of a metal salt of a hydrophobic fatty acid and a diol consisting of a dicarboxylic acid and a diphenol, prepared according to the illustrations in the examples of Developed with toner, the toner particles are retained on the recording surface in conformity with the electrostatic latent image.

This toner image was then transferred to plain paper. The paper with the electrostatically adhered toner image is then passed between a fuser roll structure and a back-up roll at a rate of about 315 inches per second, the fuser roll structure being heated to a temperature of is a type that can be adjusted in the same way as nip pressure. This toner image is 2.
A fuser roll structure is contacted that has an outside diameter of 0 inches and is 15 inches long. This back-up roll is coated with 0.02% of fluorinated ethylene-propylene resin on the surface.
It had an outside diameter of approximately 2.0 inches with a 0.1 inch layer of silicone rubber coated with a 0 inch coating. The fuser roll structure was made from metal with the finish described in the Examples below. A release agent consisting of the following materials was liquefied and metered onto the fuser roll before contacting the toner image. The fusion latitude and fusion window were then measured. In the fuser fuser and apparatus described above using a metal fuser roll, polydimethylsiloxane having a carboxy group attached to an alkyl spacer group was applied from a reservoir to the fuser roll.

By using a functionalized modified thermoplastic toner as described above and as described in the Examples of U.S. Patent No. 16.3590000, the fusing of latitude was obtained. Approximate molecular weight, viscosity at 25°C, centipoise, mole %
Indicates the amount of carboxyl functionality (-COOH) and the metal substrate of the fusing member.

Unless otherwise specified, alkyl spacer groups are straight chain propyl groups. The carboxy functionality is placed on the side chain spacer group. EXAMPLE Example 1 Using a blend of carboxypolyalkylsiloxane and silicone oil as shown in the data below.
A test similar to that in - was carried out.

The fusing latitude or window was measured for the modified toner used in Example 1-. 50/50 of the siloxane fluid of the example and the standard Xerox fusion oil (silicone oil)
A 50% formulation was made.

Fusing roll is 220-340'F for copper fusing roll
It was hot. A blend of 1 part of the example siloxane fluid and 4 parts of standard Xerox fusing oil (silicone oil) was prepared.

Fusing window is 20 for stainless steel fusing rolls
It was below 0-240. A blend of 1 part of the example siloxane fluid and 4 parts of standard Xerox fusing oil (silicone oil) was prepared.

The fusing window for this formulation containing 0.5 mole % COOH was 200280'F with respect to the copper fusing roll.

The fusing window for this formulation was 200-300'F for the aluminum fuser roll and 200-260'F for the anodized aluminum fuser roll.
EXAMPLE When performed in a similar manner, no fused windows or latitudes were observed.

However, the same release agent is conventional non-reactive (non-functional)
It had a fusing window for the toner. Example M
The toner of Example 1 was used on bare copper rolls, bare aluminum rolls, and bare stainless steel rolls.

In both cases, release defects were immediately apparent at the lowest fusing temperature as evidenced by offset on the roll. EXAMPLE The toner of Example 1 was fused onto a copper, aluminum, and stainless steel fuser roll coated with polydimethylsiloxane fluid (silicone oil).

Immediate release defects were observed at the lowest fusing temperature in both cases. Data from the foregoing examples show that reactive toners or modified toners having functional groups that react with the fusing member are
It is shown that it can be fused without offsetting with a bare metal fusion member coated with a polyalkylsiloxane having carboxy functionality.

In all of the above examples in which carboxy-functional polydimethylsiloxane was used as a release agent on the fuser roll, it was found that the modified reactive type toner was excluded from the flaws and grooves in the coating and that the bare metal fused It has been observed that the modified toner that actually comes into contact with the transfer member is excluded by the carboxy-functional polydimethylsiloxane, and that this toner is not picked up by the breaks in the film to cause toner deposits on subsequent copies. . In accordance with the foregoing objects, a fusing method and fusing member have been presented for fusing toner images of modified toners.

In all cases except Example M, the fusing member was found to be self-healing and its surface was continuously reproducible. In the above experiments with release agents, it was observed that modified toner was actually displaced from the exposed surface of a fusing member coated with a polymeric fluid having carboxy functional groups thereon by the action of the release agent. The above experiments were conducted by trenching the surface area so that the toner material remained on the metal surface. Even in that case, the modified toner material was actively removed from the surface of the fusing member by the action of the release agent, and toner contamination of subsequent copies was avoided. Although the invention has been described with respect to preferred embodiments, it will be obvious that certain modifications and changes can be made without departing from the spirit and scope of the invention and, therefore, the foregoing description is limited only by the appended claims. intended to be done.

[Brief explanation of drawings]

FIG. 1 is a typical side elevation view of a fusing system for a xerographic reproduction machine.

Claims (1)

[Claims] 1. The surface of a fusing member in an electrostatographic reproduction device comprising applying to the fusing member a polyalkylsiloxane fluid capable of eliminating modified electroscopic thermoplastic resin toners having functional groups that react with the metal of the fusing member. wherein the fluid has carboxy functional groups capable of interacting with a surface of a fusing member to produce a thermally stable interfacial layer, and the surface is bonded to at least one continuous layer of the fluid. applied in an amount sufficient to coat with a low surface energy film to release modified thermoplastic toner heated by the fusing member and prevent the modified thermoplastic toner from contacting the surface of the fusing member; 1. A method comprising: providing a fusing member with a surface that