Apparatuses useful in printing and methods of fixing marking material on media

Apparatuses useful in printing and methods of treating marking material on media are disclosed. An embodiment of the apparatuses includes a roll including a first outer surface; a continuous belt including an inner surface and a second outer surface forming a nip by contact with the first outer surface, the belt being driven by rotation of the roll; and a heater disposed inside of the belt. The heater includes a circumferentially-extending heating surface contacting the inner surface of the belt over an angle of at least about 90°.

BACKGROUND

In printing processes, images can be formed on media using marking material. Apparatuses used in such processes can include opposed members that form a nip. During printing processes, the marking material on the media is treated at the nip using the opposed members.

It would be desirable to provide apparatuses useful in printing that are more compact and can provide desirable heating and energy consumption characteristics, and to provide methods for treating marking material on media that can use such apparatuses.

SUMMARY

Embodiments of apparatuses useful for printing and methods of fixing marking material on media are disclosed. An exemplary embodiment of the apparatuses useful in printing comprises a roll including a first outer surface; a continuous belt including an inner surface and a second outer surface forming a nip by contact with the first outer surface, the belt being driven by rotation of the roll; and a heater disposed inside of the belt. The heater includes a circumferentially-extending heating surface contacting the inner surface of the belt over an angle of at least about 90°.

DETAILED DESCRIPTION

The disclosed embodiments include an apparatus useful in printing comprising a roll including a first outer surface; a continuous belt including an inner surface and a second outer surface forming a nip by contact with the first outer surface, the belt being driven by rotation of the roll; and a heater disposed inside of the belt. The heater includes a circumferentially-extending heating surface contacting the inner surface of the belt over an angle of at least about 90°.

The disclosed embodiments further include an apparatus useful in printing comprising a roll including a first outer surface; a continuous belt including an inner surface and a second outer surface, the belt being driven by rotation of the roll; a first nip formed by the second outer surface contacting the second first surface, the first nip including an inlet end where media enter the first nip and a first outlet end where media exit the first nip; a second nip formed by the second outer surface contacting the first outer surface adjacent the outlet end of the first nip, the second nip extending from about the first outlet end of the first nip to a second outlet end; a heater disposed inside of the belt, the heater including a heating surface contacting the inner surface of the belt; and a stripping member disposed inside of the belt. The stripping member includes a surface configured to contact the inner surface of the belt to produce a stripping force effective to assist stripping of media from the second outer surface after the media exit from the first nip.

The disclosed embodiments further include an apparatus useful in printing comprising a roll including a first outer surface; a continuous belt including an inner surface and a second outer surface forming a nip by contact with the first outer surface, the belt being driven by rotation of the roll; and a heater disposed inside of the belt. The heater includes a heating surface contacting a portion of the inner surface of the belt circumferentially spaced from the nip. The apparatus does not include a heater that heats the inner surface of the belt at the nip.

FIG. 1illustrates an exemplary printing apparatus100disclosed in U.S. Pat. No. 7,228,082, which is incorporated herein by reference in its entirety. As used herein, the term “printing apparatus” encompasses any apparatus, such as a digital copier, bookmaking machine, multifunction machine, and the like, or portions of such apparatuses, that can perform a print outputting function for any purpose. The printing apparatus100can be used to produce prints from various types of media, such as coated or uncoated (plain) paper sheets, having various sizes and weights.

The printing apparatus100includes a fuser110with a rotatable, continuous belt112and a pressure roll120defining a nip122. The printing apparatus100further includes a rotatable photoreceptor130. To form a toner image on the photoreceptor130, a charging device140is activated to charge the outer surface of the photoreceptor130. The photoreceptor130is rotated to an exposure device150to form an electrostatic latent image on the photoreceptor130. Then, the photoreceptor130is rotated to a developer device160, which applies marking material (toner) to the electrostatic latent image to form the toner image on the photoreceptor130. The toner image is transferred from the photoreceptor130to a medium162, e.g., a sheet of paper, conveyed from a sheet supply stack164. The medium162on which the toner image has been formed is conveyed to the nip122of fuser110. The printing apparatus100includes a controller170configured to control operation of the image-forming devices during printing. After the medium162passes through the nip122, the medium is conveyed to an output tray180. A cleaning device182removes residual toner particles from the photoreceptor182before the imaging process is repeated for another medium.

Apparatuses useful in printing are provided. Embodiments of the apparatuses can be used to fix marking materials on media. The apparatuses include opposed members for applying heat and pressure to media to fix marking material onto the media.

FIG. 2illustrates an exemplary embodiment of the apparatuses useful in printing. The apparatus is a fuser200for fixing marking material on media. Embodiments of the fuser200can be used in various printing apparatuses, e.g., in the printing apparatus100shown inFIG. 1in place of the fuser110.

The fuser200includes a continuous fuser belt210with an outer surface212and inner surface214. A pressure roll220including an outer surface222is shown positioned in contact with the outer surface212of the fuser belt210to form a nip224. In embodiments, the pressure roll220is a drive roll and the fuser belt210is driven by engagement with the pressure roll220, i.e., free-spinning. The pressure roll220is rotated clock-wise to cause the belt to rotate counter-clockwise. Media are conveyed through the nip224in process direction A. The media can be, e.g., paper sheets with at least one toner image, transparencies, and the like on a surface of the media that is contacted by the outer surface212of the fuser belt210. At the nip224, opposite faces of the media contact the outer surface212of the fuser belt210and the outer surface222of the pressure roll220.

Embodiments of the fuser belt210can include two or more layers. The layers can each comprise a polymeric material. For example, the fuser belt210can include a base layer forming the inner surface214, an intermediate layer overlying the base layer, and an outer layer forming the outer surface212, overlying the intermediate layer. The inner layer can be composed of polyimide, or the like; the intermediate layer of silicone, or the like; and the outer layer of a fluoropolymer having low-friction properties, such as polytetrafluoroethylene (Teflon®), or the like. Typically, the base layer can have a thickness of about 50 μm to about 100 μm, the intermediate layer a thickness of about 100 μm to about 300 μm, and the outer layer a thickness of about 10 μm to about 40 μm. The fuser belt320can typically has a width of about 215 mm to about 450 mm. In embodiments, the fuser belt210is cylindrical shaped when un-deformed. The fuser belt210has a thickness and composition that allows it be elastically deformed.

In other embodiments, the fuser belt210can be comprised of a metal or metal alloy, such as steel, stainless steel, or the like, forming the base layer. One or more layers can overly the base layer. These layers can include an intermediate layer comprised of an elastic material, such as silicone, or the like, and an outer layer comprised of a fluoropolymer having low-friction properties, such as Teflon®, or the like.

The pressure roll220includes a core224, an inner layer226on the core224, and an outer layer228on the inner layer226. The core224can be comprised of a metal, metal alloy, or the like; the inner layer226of an elastic material, such as silicone or the like; and the outer layer228of a low-friction material, such as Teflon®, or the like.

A heater230is located inside of the fuser belt210. The heater230is positioned on a support member240. The support member240is supported on a nip member260.

In embodiments, the heater230is stationary and the fuser belt210rotates relative to the heater230. The heater230is configured to heat a substantial portion of the fuser belt210rapidly to the desired temperature for fixing marking material onto media at nip224.

The heater230contacts the support member240and includes an outer heating surface232contacting the inner surface214of the fuser belt210. In embodiments, the heating surface232has a curved shape. For example, the heating surface232can be semi-circular-shaped, as shown, elliptical-shaped, or the like. In the embodiment, both ends of the heater230are circumferentially spaced from the nip member260, and the entire heater230is supported on the support member240. The heating surface232can extend circumferentially over an angle of about 90° up to about the entire portion of the inner surface214that does not contact the nip member260(i.e., 360°—the angle of the inner surface214that is contacted by the nip member260). For example, the angle can be at least about 120°, at least about 150°, at least about 180°, at least about 210°, at least about 240°, at least about 270°, at least about 300°, at least about 330°, or higher. The heater230extends longitudinally or axially along the fuser belt210. In embodiments, a low-friction backer or support member can be used to support a portion of the fuser belt210that is not supported by the heating surface232or nip member260.

In embodiments, at a given maximum thermal output of the heater230(e.g., the maximum power density), increasing the arc length of the fuser belt210that is heated by contact with the heating surface232(i.e., increasing the angle of the heating surface232) can increase the productivity of the fuser200. The productivity can be expressed, e.g., as the number of prints per minute of a given media type that can be run in the fuser200, without exceeding a maximum operating temperature of the fuser belt210. The heater230can be operated at a lower maximum temperature to heat the fuser belt210to a given set temperature by increasing the arc length of the fuser belt210heated by the heater230.

In embodiments, the heater230is a ceramic heater. The ceramic heater can comprise a single ceramic plate, or multiple ceramic plates. The ceramic plates can be heated quickly to a desired temperature. The plates of the heater230can be comprised of one or more suitable ceramic materials. The ceramic materials have sufficiently-high thermal conductivity to transfer thermal energy to the fuser belt210rapidly when the heater230is activated. For example, the ceramic materials can be selected from quartz, and the like. In embodiments, the heater230has a low thermal mass and can be rapidly heated when activated. For example, plates of the heater230can have a radial wall thickness of about 0.5 mm to about 5 mm.

The heating surface232can have a smooth finish to reduce friction between the heating surface232and the inner surface214of the fuser belt210during rotation of the fuser belt210.

In embodiments, the heater230can include one or more heating elements (not shown) for heating the heating surface232. The heating elements can extend circumferentially about the heater230and along the longitudinal axis of the fuser belt210. The heating elements can be embedded in the heater230, and/or provided on an outer surface. The heating elements can be connected to a power supply270. A controller280is connected to the power supply270to control the amount of power supplied by the heating elements to heat the fuser belt210. In embodiments, the heating elements can heat substantially the entire heating surface232in contact with the fuser belt210.

In embodiments, the heater230can include a plurality of separate heater segments positioned in series along the axial direction of the fuser belt210.FIG. 3shows an exemplary embodiment of a segmented heater330including three heater segments; namely, a first heater segment332having a heating surface333, a second heater segment334having a heating surface335, and a third heater segment336having a heating surface337. The heating surfaces333,335and337contact the inner surface214of the fuser belt210at axially-spaced locations. The heating surfaces333,335and337are curved. For example, the heater segments can each have a semi-circular (ring) configuration, with the same inner diameter and outer diameter, an elliptical configuration, or the like. The heater segments can each comprise a single plate, or multiple plates. As shown, the first heater segment332has a width W1, the second heater segment334has a width W2, and the third heater segment336has a width W3, along the axial direction B. The widths W1, W2and W3can be selected based on the size of media typically used in the fuser200(i.e., the media dimension along the axial direction B).

In embodiments, the first heater segment332, second heater segment334and third heater segment336can each include at least one heating element. The heating element(s) of the first heater segment332, second heater segment334and third heater segment336, respectively, can be selectively addressed depending on the selected region of the outer surface212of the fuser belt210to be heated. The region of the outer surface212that is to be heated can be determined based on common media widths used in the fuser200and the registration of the media (i.e., inboard registered, outboard registered or center registered). The heating elements of the first heater segment332, second heater segment334and third heater segment336can be connected to the power supply270and controller280.

As shown inFIG. 2, the support member240includes a first member242and a second member244. The first member242includes a curved portion246and a first wall248. The curved portion246can be semi-circular shaped, for example. In the embodiment, the curved portion246contacts the heater230over the entire circumferential extent of the heater230. The second member244includes a base250and a second wall252. The support member240extends along the longitudinal axis of fuser belt210. In embodiments, the first member242and second member244can comprise metallic, ceramic, or composite materials. At least one spring member254, e.g., at least one compression spring, or the like, is positioned between the first wall248and second wall252. The second member244is fixed (stationary) in the fuser200. The first member242can move upwardly and downwardly relative to the second member244, as indicated by arrows C inFIG. 2. The spring members254resiliently bias the first member242away from the second member244and against the heater230, which increases tension in the fuser belt210. The spring forces exerted by the spring members254can be selected to control the amount of tension in the fuser belt210.

The nip member260includes a stripping member262configured to assist stripping of media from the outer surface212of fuser belt210. The nip member260can comprise a single piece of material. The nip member260also includes a contact surface264. The contact surface264can be planar, as shown. As shown inFIG. 2, the portion of the fuser belt210in contact with the contact surface264is elastically deformed to form a first nip, N1(“primary nip”), with the outer surface222of the pressure roll220. The first nip N1extends from an inlet end, IE, at which media enter the first nip N1, to an opposite outlet end, OE, at which the media exit the first nip N1.

The position of the pressure roll220is adjustable relative to the fuser belt210(whose position can be fixed) to adjust the amount of pressure applied by the pressure roll220to the fuser belt210at the first nip N1. For example, a mechanism can be operatively connected to the pressure roll220to move the pressure roll220toward or away from the fuser belt210as indicated by arrows D to adjust the applied pressure.

The inner layer226of the pressure roll220is sufficiently compressible when the pressure roll220applies pressure to the fuser belt210such that the outer layer228is depressed to form the first nip N1. Increasing the amount of pressure applied by the pressure roll220against the fuser belt210increases the degree of deformation of the inner layer226, which increases the width of the first nip N1(between the inlet end IE and outlet end OE) formed by contact between the outer surface222and outer surface212adjacent the contact surface264of the nip member260.

The first nip N1can typically have a width in the process direction A between the inlet end IE and outlet end OE of about 10 mm to about 15 mm. The nip width can be expressed as the product of dwell time and process speed (i.e., nip width=dwell×process speed). The dwell time is the amount of time that a medium remains in contact with the outer surface212of the fuser belt210as the medium passes through the first nip N1. A small width of N1is desirable for light-weight media, while a higher width is desirable for heavy-weight media. At typical process speeds at which media can be fed to the nip224, the dwell time at the first nip N1can typically be about 30 ms to about 40 ms. The fuser200can typically be run at a printing speed of about 50 to about 100 pages per minute for media weights ranging from light-weight to heavy-weight.

In embodiments, the characteristics of media and images carried on the media can be considered in determining optimum settings in the fuser200. For example, it is desirable to have increased fusing (i.e., a higher temperature, pressure and/or dwell) for images with large media area coverage, and less fusing (i.e., a lower temperature, pressure and/or dwell) for text documents. The adjustability of the width and pressure of the first nip N1allows these parameters to be set to optimum levels for different types of media and different images.

The heater230can supply sufficient thermal energy to the fuser belt210to heat the outer surface212to a sufficiently-high temperature to fix different types of marking material on different types of media (e.g., coated or uncoated media with different weights) at the first nip N1at these dwell times.

In the embodiment of the fuser200shown inFIG. 2, the nip member260does not include a separate heater to supply thermal energy to the fuser belt210at the region of the nip224. In the embodiment, the fuser belt210is directly heated only where the heating surface232contacts a portion of the inner surface212circumferentially spaced from the nip224. In the embodiment, the fuser200does not include a heater that heats the inner surface212at the nip224. In embodiments, the pressure roll220is typically not internally heated. The outer surface222is heated by contact with the heated fuser belt210. A minimum temperature of the outer surface222may be desirable prior to print runs.

In other embodiments of the fuser200, the nip member260can also include a heater to supplement the thermal output of the heater230. In such embodiments, the heater of the nip member260supplies thermal energy across the contact surface264to heat the fuser belt210at the first nip N1.

The portion of the fuser belt210adjacent to the outlet end OE of the first nip N1forms a second nip (or “secondary nip”), N2, by contact between the outer surface212and the outer surface222of the pressure roll220. As shown inFIGS. 4 and 5, the second nip N2extends from about the outlet end OE of the first nip N1to a stripping end, SE, at which the fuser belt210separates from the outer surface222. The fuser belt210contacts the outer surface222continuously from the outlet end OE to the stripping end SE.

The stripping member262includes a stripping edge266and an outer surface268extending from the stripping edge266. At the stripping edge266, the fuser belt210bends at a stripping angle, α, away from the outer surface222of pressure roll220. The stripping angle α can typically be from about 15° to about 90°.

The stripping member262can be comprised of any suitable material, such as a metal, e.g., steel, aluminum, aluminum alloys, or the like; a polymer, such as a plastic having sufficient wear resistance and temperature resistance, or the like. A coating of a low-friction material can be provided on the stripping edge266and outer surface268to reduce wear of the inner surface214of the fuser belt210during its rotation. For example, the low-friction material can be Teflon®, or the like. The stripping member262has a sufficient length in the axial direction of the fuser belt210to contact the entire dimension of the fuser belt210that defines the media path through the nip224.

In embodiments, the stripping edge266of the stripping member262has a curvature that produces a sufficiently-high stripping force to mechanically separate (strip) media from the outer surface212of the fuser belt210. For example, the stripping edge266can have a semi-circular, parabolic, elliptical, or like shape that provides the desired stripping assistance. For a semi-circular shape, the curvature of the stripping edge266is described by a radius. Reducing the radius increases the curvature of the stripping edge266, and increases the stripping force produced by the stripping edge266. In embodiments, the radius describing the curvature of the stripping edge266can range in length from about 0.5 mm to about 5 mm. Reducing the radius of the stripping edge266increases the stripping force. Increasing the stripping angle increases stripping dwell, which allows a higher stripping force to be achieved. The radius of the stripping edge266can be based on the type of media most commonly used in the fuser200. Reducing the curvature of the stripping edge266reduces wear of the inner surface214of the fuser belt210. In embodiments, the largest radius (smallest curvature) of the stripping edge266that produces a sufficiently-high stripping force to strip the type of media normally run in the fuser200can be used to reduce wear of the fuser belt210. For example, a large radius (small curvature) of about 4 mm to about 5 mm may be desirable in embodiments of the fuser200that normally run heavy-weight media. A small radius (large curvature) of about 0.5 mm to about 2 mm may be desirable in embodiments of the fuser200that normally run light-weight media.

Although the above description is directed toward fuser apparatuses used in xerographic printing, it will be understood that the teachings and claims herein can be applied to any treatment of marking material on media. For example, the marking material applied on media can be toner, liquid or gel ink, and/or heat- or radiation-curable ink; and/or the media can utilize certain process conditions, such as temperature, for successful printing. The process conditions, such as temperature, pressure and other conditions that are desired for the treatment of ink on media in a given embodiment may be different from the conditions suitable for xerographic fusing.