Patent Publication Number: US-11047630-B2

Title: Fuser assemblies

Description:
BACKGROUND 
     Inkjet printers can deposit quantities of printing fluid onto a printable media (e.g., paper, plastic, etc.). In some examples, inkjet printers can create a curl and/or cockle in the printed media when the printing fluid droplets deposited by the inkjet printer are not completely dry. In some examples, a number of physical properties of the printable media can be changed when the printing fluid droplets deposited by the inkjet printer are not completely dry. For example, the stiffness of the printable media can be changed when the printing fluid droplets deposited by the inkjet printer are not completely dry. The curl, cockle, and/or other physical properties that change due to the printing fluid droplets can make finishing processes difficult. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic cross-sectional diagram of an example fuser assembly to operate with a roller in accordance with aspects of the present disclosure. 
         FIG. 2  is a schematic cross-sectional diagram of a media conditioner including an example fuser assembly and rollers in accordance with aspects of the present disclosure. 
         FIG. 3  is a schematic cross-sectional diagram of a media conditioner including another example fuser assembly and a roller in accordance with aspects of the present disclosure. 
         FIG. 4  is a schematic diagram of an example system including a media conditioner for use with a printing device and finishing device in accordance with aspects of the present disclosure. 
         FIG. 5  is a flow diagram illustrating an example media conditioning method in accordance with aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific examples in which the disclosure may be practiced. It is to be understood that other examples may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims. It is to be understood that features of the various examples described herein may be combined, in part or whole, with each other, unless specifically noted otherwise. 
     Finishing (e.g., aligning, stapling, stacking) of un-dried or partially dried inkjet media output can be difficult. Many finisher devices and methods are not suited for working with partially dried inkjet output as the printed media can be distorted from curl and cockle and/or can have reduced stiffness from increased moisture content, for example. Additionally, the surface roughness increases due to increased moisture when the media is printed upon which, in turn, increases the sheet to sheet friction of the media. A number of systems and devices for partially dried inkjet media fusers are currently available. Forms of drying involving a single fuser are not able to counteract curl and other distorted property of undried or partially dried media and additional forms of drying systems are often employed. 
     In addition to causing printer damage and/or shutdown, too much heat applied in one location can also adversely affect product quality. In particular, too much moisture may be driven out of the edges of narrower media by the adjoining high heat. When this occurs, excessive media curl or wave, caused by differences in moisture content across the media, develop and produce a product of substandard appearance. In some cases of elevated, focused heat application, scorching or burning of the media can occur. 
     In accordance with aspects of the present disclosure, a media conditioner including a fuser assembly can be utilized to apply pressure and heat to the undried inkjet media to restore the distorted properties caused by the printing fluid absorbed by the media. The media can be printed on one or both sides. The media conditioner can remove moisture from the media after printing and prior to proceeding to a finishing device. The media conditioner can be connected between the printing device, or printing head, and the finishing device. The media conditioner can be utilized to enhance drying of the printing fluid with pressure and heat across a series of contact zones as described further below. 
       FIG. 1  is a schematic cross-sectional diagram of an example fuser assembly  10  to operate with a roller  55  in accordance with aspects of the present disclosure. Fuser assembly  10  includes a fuser housing  52  and an array of fusers  54  disposed in fuser housing  52 . Each fuser  54   a ,  54   b ,  54   c  of array of fusers  54  includes a heating element  53  exposed along a surface  57  of fuser housing  52  and adjacent to an outer surface  59  of roller  55 . 
       FIG. 2  illustrates an example media conditioner  150  including a fuser assembly  100  consistent with the present disclosure. Fuser assembly  100  includes a fuser housing  102  and an array of fusers  104 . Array of fusers  104  are disposed, or contained, within openings  106  in a body  108  of fuser housing  102 . A belt  110  encircles fuser housing  102 . Belt  110  is tubular and encircles an exterior surface  112  of fuser housing  102 . Belt  110  is movable along exterior surface  112  of fuser housing  102  and array of fusers  104 . Belt  110  has good heat conduction, low thermal mass, and handles forces of compression and friction while traveling through contact zones  134  (described in more detail below). Belt  110  can be formed of a lamination of plastics and/or metal, for example, although other suitable materials are also acceptable. 
     Fuser housing  102  can be elliptical in cross-section and include array of fusers  104  positioned linearly, as illustrated in  FIG. 1 . Other appropriate shapes of fuser housing  102  suitable to accommodate positioning each fuser  104   a ,  104   b ,  104   c  of array of fusers  104  against a roller  105  are also acceptable. In one example, fuser housing  102  is formed of a solid plastic, although other materials, including multiple materials and/or non-solid forms, can be employed in fuser housing  102 . 
     In some examples, each or at least one, fuser in array of fusers  104  extends substantially an entire length of fuser housing  102 . Array of fusers  104  is operably associated within fuser housing  102 , with each fuser  104   a - 104   c  including a heating element  114  exposed at each opening  106  along exterior surface  112  of fuser housing  102 . Heating element  114  can be, in some cases, aligned with exterior surface  112  of fuser housing  102 . 
     With additional reference to the enlarged exemplary fuser  104   c  illustrated in Inset A, each fuser  104   a ,  104   b ,  104   c  includes a channel  116 , or inverted trough, disposed within opening  106  of fuser housing  102 . In one example, channel  116  is formed in as an elongated open sided rectangle, including two opposing sides  118   a ,  118   b  and a bottom  120  extending between the two opposing sides  118   a ,  118   b . Other suitable shapes of channel  116  can also be employed, such as U-shaped, square, etc. Channel  116  includes an open side  122 , for example, opposite bottom  120  having a width substantially equivalent to a width of opening  106  at exterior surface  112  of fuser housing  102 . Open side  122  is positioned along exterior surface  112  of fuser housing  102  such that an interior of channel  116  is fluidly open to the exterior. Opposing sides  118   a ,  118   b  terminate flush with or inset into opening  106  of fuser housing  102 . Channel  116  provides rigidity and support to each respective fuser  104   a ,  104   b ,  104   c  and maintains respective fuser  104   a ,  104   b ,  104   c  alignment within fuser housing  102 . Channel  116  can be constructed of metal, such as sheet metal, or other rigid material, for example. 
     A mount  124  is provided on the interior of channel  116 . Mount  124  can be disposed along bottom  120  of channel  116  and extend fully between opposing sides  118   a ,  118   b . In one example, mount  124  occupies the entire interior of channel  116 . Mount  124  is coupled to channel  116  with an adhesive, mechanical fastener, or other appropriate mechanism. Mount  124  can provide additional support and rigidity to the respective fuser  104   a ,  104   b ,  104   c . Mount  124  can be formed of a non-conductive material, such as plastic, for example. Substrate  126  is attached to mount  124  along open side  122  of channel  116 . Substrate  126  can be formed as a layer having a first major surface  128  and an opposing second major surface  129  opposite first major surface  128 . Substrate  126  can be formed of ceramic or other thermally insulative material. Substrate  126  can extend over the entire, or substantially entire, exposed surface of mount  124 . 
     Substrate  126  is attached to mount  124  and heating element  114  is disposed on substrate  126 . Heating element  114  is disposed on first major surface  128  of substrate  126 . Each fuser in array of fusers  104  can have separately controllable heating elements  114  and can be controlled to deliver a different degree of heat. In one example, each heating element  114  will deliver a graduated higher or lower heat level than delivered to adjacent fusers in array of fusers  104 . In another example, each heating element  114  will deliver the same heat level to each fuser in array of fusers  104 . 
     Heating element  114  can include a resistive heat trace  130 . In some examples, resistive heat trace  130  extends linearly along a length of fuser  104   a ,  104   b ,  104   c . In some examples, resistive heat trace  130  is a conductive wire disposed on substrate  128  and extends in two parallel rows along the length of fuser  104   a ,  104   b ,  104   c . In one example the heat trace wires can be spaced 5 mm to 8 mm apart from one another on the fuser  104   a ,  104   b ,  104   c . Other spacing of the heat trace wires can be utilized as appropriate for drying the printed media. Additionally, a protective coating (not shown), such as glass, can be disposed over resistive heat trace  130 . Regardless, heating elements  114  each define a heat zone such that equal heat is emitted along the substantially the entire length of the respective fuser  104   a ,  104   b ,  104   c  to evenly condition the media across the media&#39;s entire width as the media passes between fuser assembly  100  and roller  105 . 
     With continued reference to  FIG. 2 , fuser assembly  100 , and in particular, array of fusers  104  housed therein, are disposed adjacent rollers  105 . Array of fusers  104  can be disposed in a spaced apart, parallel arrangement within fuser housing  102 . A distance between adjacent fusers (e.g., fuser  104   a  and  104   b , etc.) is suitable to correspond to a diameter of roller  105  and operational space between adjacent rollers to allow rollers  105  to freely rotate. Rollers  105  are positioned for cooperative interaction with fuser assembly  100  and array of fusers  104  such that contact zones  134  are formed by each respective fuser of array of fusers  104  in cooperation with the associated roller(s)  105  to apply heat and pressure to the media as it passes between fuser assembly  100  and roller  105 . Array of fusers  104  can be disposed in a spaced apart, parallel arrangement within fuser housing  102 . 
     Roller  105  and fuser assembly  100  work in cooperative unison to respectively provide thermal energy for drying the media and provide pressure to smooth the media fibers. A force, as indicated by arrow “F”, can be applied by each roller  105  toward the associated, respective fuser  104   a ,  104   b ,  104   c . In one example, force “F” can be independently controlled at each roller. Alternatively, force “F” applies equal pressure at each roller  105 . In some examples, force “F” is a normal force applied perpendicularly toward each fuser  104   a ,  104   b ,  104   c . Regardless, force “F” is evenly applied along a respective roller  105 . Rollers  105  can be compressively resilient and deflect as necessary in response to application of force “F” against fusers  104   a ,  104   b ,  104   c  to provide consistent contact between roller  105  and heat element  114  across each respective contact zone  134 . In one example, roller  105  has a rigid steel shaft surrounded by a compliant rubber having a smooth exterior surface. Roller  105  can be cylindrical and rotatable in a clockwise or counter-clockwise (e.g., first or second direction) to assist in moving the media past fusion assembly  100  and through media conditioner  150 . In one example, rollers  105  rotate in a direction indicated by arrow  160  and belt  110  on fuser assembly  100  rotates in a direction indicated by arrow  162 . Roller  105  has a length dimension measured along its cylindrical axis. In some examples, roller  105  and fuser housing  102  are substantially the same length. 
     Although three fusers  104   a ,  104   b ,  104   c  and corresponding rollers  105  are illustrated in  FIG. 2 , it is understood that more or less can be employed to accomplish the desired media conditioning. Each fuser of array of fusers  104  is disposed adjacent an outer surface of roller  105 . In some examples, fuser assembly  100  can be in contact with rollers  105  when in an operating state and/or in a non-operating state. 
       FIG. 3  illustrates another example of media conditioner  250  including a fusion assembly  200  in accordance with aspects of the present disclosure. Fuser assembly  200  is similar to fuser assembly  100  in many aspects, with like elements numbered similarly. Fuser assembly  200  includes a fuser housing  202  suitable to accommodate an array of fusers  204  arranged along a line of curvature  207  corresponding to a circumference of a roller  205 . Fuser housing  202  can be elliptically curved, or kidney-bean shaped, for example, to accommodate roller  205 . Fusers in array of fusers  204  are positioned radially with respect to one another along line of curvature  207 . Array of fusers  204  can be positioned closely together within a single opening  206  of fuser housing  202 . A belt  210  encircles fuser housing  202 , extending across opening  206  and array of fusers  204 . 
     Each fuser  204   a ,  204   b ,  204   c  in array of fusers  204  have a heating element  214  exposed along the outer surface of the fuser housing  202 . Each fuser  204   a ,  204   b ,  204   c  in array of fusers  204  includes a channel  216 , a mount  224 , and a substrate  226  upon which heating element  214  is mounted. Heating element  214  includes a resistive heat trace  230  extending along a length of the respective fuser  204   a ,  204   b ,  204   c.    
     Roller  205  has a diameter such that fuser assembly  200  can be positioned around at least a portion of an outer surface of roller  205 . Although three fusers  204   a ,  204   b ,  204   c  are illustrated in  FIG. 2 , it is understood that more or less can be employed to accomplish the desired media conditioning. Each fuser of array of fusers  204  is disposed adjacent an outer surface of roller  205 . In some examples, fuser assembly  200  can be in contact with roller  205  when in an operating state and/or in a non-operating state. 
     Fuser assembly  200  and roller  205  work in cooperative unison to respectively provide thermal energy for drying the media and provide pressure to smooth the media fibers. A force, as indicated by arrows “FF”, can be applied independently by each fuser  204   a ,  204   b ,  204   c  toward roller  205 . Each fuser  204   a ,  204   b ,  204   c  is independently moveably mounted within opening  106  to accommodate independent application of forces “FF”. Forces “FF” can be applied normal, or perpendicular to, outer surface of roller  205 . In one example, pressure applied by force “FF” can be independently controlled at each fuser  204   a ,  204   b ,  204   c . Alternatively, force “FF” applies equal pressure at each roller  105 . Regardless, force “FF” is evenly applied along a respective fuser  204   a ,  204   b ,  204   c . Roller  205  can be compressively resilient and deflect as necessary in response to application of forces “FF” to provide consistent contact between roller  205  and heat elements  214  across each respective contact zone  234 . Roller  205  can be cylindrical and rotatable in a clockwise or counter-clockwise (e.g., first or second direction) to assist in moving the media past fusion assembly  200  and through media conditioner  250 . In one example, roller  205  rotate in a direction indicated by arrow  260  and belt  210  on fuser assembly  200  rotates in a direction indicated by arrow  262 . Roller  205  has a length dimension measured along its cylindrical axis. In some examples, roller  205  and fuser housing  202  are substantially the same length. 
     Rollers  105 ,  205  can be positioned below, beside, or above fuser assemblies  100 ,  200 , as long as respective rollers  105 ,  205  and respective array of fusers  104 ,  204  housed within fuser housing  102 ,  202  are disposed adjacently and within contact of one another. Fuser assemblies of the present disclosure, such as fuser assemblies  100 ,  200 , can be utilized to restore a number of distorted properties of dried inkjet media to perform a finishing process. As described herein, the number of distorted properties of undried or partially dried inkjet media can cause problems when attempting to perform a finishing process. 
       FIG. 4  illustrates an example system  300  including a media conditioner  305  for use with a printing device  370  and a finishing device  380  in accordance with aspects of the present disclosure. In some examples, media conditioner  305  (including a fuser assembly such as fuser assembly  100  or fuser assembly  200 ) can be coupled between printing device  370  (e.g., inkjet printer, etc.) and finishing device  380  (e.g., finisher, etc.). For example, media conditioner  305  can provide dried flat inkjet media with reduced friction to finishing device  380  for performing finishing processes (e.g., stacking, collating, stapling, hole punching, binding, etc.). In other examples, media conditioner  305 , and associated fuser assembly, can be included within either printing device  370  or finishing device  380 . The resulting dried media is able to be used with finishers and other post print devices. 
     As described above, fusers assemblies  100 ,  200  can provide drying while the media is constrained, such as between rollers  105  and fuser housing  102 , for example. Array of fusers  104 ,  204  can provide a multi-stage media conditioning (i.e., each fuser in array of fusers  104  creating a different stage of drying) allowing the printed media to progressively dry which helps stabilize the media&#39;s tendency to curl. Fusing also compresses the surface fibers thereby reducing surface friction. Array of fusers  104 ,  204  creates repetition of drying and surface compression. The repeated application of fusing yields progressive benefit towards a flat dry media sheet with a smooth surface. 
       FIG. 5  is a flow diagram illustrating a method  400  of conditioning media in accordance with aspect of the present disclosure. At  402 , a roller is rotated in a first direction. At  404 , a tubular belt is rotationally moved around an array of fusers disposed within a fuser housing. At  406 , media is passed between the array of fusers and the roller. At  408 , heat is applied from the array of fusers to the passing media. At  410 , a force is applied to compress the media between the roller and the array of fusers. At  412 , the roller is deformed against the array of fusers. At  414 , a contact area is formed along each of the fusers in the array of fusers against the roller. At  416 , a printing fluid applied to the media is dried and fibers of the media are smoothed. 
     Although specific examples have been illustrated and described herein, a variety of alternate and/or equivalent implementations may be substituted for the specific examples shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific examples discussed herein. Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof.