Patent Publication Number: US-7907859-B2

Title: Method and apparatus for automatically adjusting nip width based on a scanned nip image on ultraviolet (UV))-sensitive media in an image production device

Description:
BACKGROUND 
     Disclosed herein is a method for automatically adjusting nip width based on a scanned nip print image on ultraviolet (UV)-sensitive media in an image production device, as well as corresponding apparatus and computer-readable medium. 
     The nip width is the measured arc distance created by the intersection of a soft fuser roll and a hard pressure roll in an image production device, such as a printer, copier, multi-function device, etc, which enables heat transfer and pressure needed to fuse prints. If the nip width is not set properly, toner is improperly melted and pressed (fused) against the paper resulting in image quality defects. In addition, improper nip setting can result in excessive wear of the fuser roll surface which results in image quality defects in the form of areas containing unacceptable differential gloss. 
     An accurate and consistent nip width increases fuser roll life by helping to minimize edge wear on the roll. It has been shown that uneven and excessive nip settings, inboard to outboard, result in accelerated edge wear. The nip width is supposed to be checked and adjusted with every fuser roll replacement. This measurement is not always done and combined with roll hardness varying significantly between batches, the roll nip widths are frequently set incorrectly. In addition, as the fuser roll ages the softness of the rubber changes resulting in less-than-optimum nip widths. 
     Conventional nip set up procedure requires the operator to manually load a blank piece of paper into the fuser nip to make an impression, dust the impressions with toner, and then measure the nip width with a small scale. Although this procedure is in the service documentation, it is not often performed with each fuser roll change. This manual process also leads to nip width variability. Although the variability may be within specification, it still results in significant delta gloss variability due to edge wear. 
     SUMMARY 
     A method and apparatus for automatically adjusting nip width based on a scanned nip print image on ultraviolet (UV)-sensitive media in an image production device is disclosed. The method may include receiving a signal to generate a nip print, automatically inserting a sheet of UV-sensitive media into a fuser nip in the image production device, pausing the sheet of UV-sensitive media in the fuser nip for a predetermined time period, illuminating the UV-sensitive media with ultraviolet light to generate a nip print, scanning the generated nip print, determining if a nip width adjustment is required based on the scanned nip print, and if it is determined that a nip width adjustment is required based on the scanned nip print, adjusting the nip width using a nip width adjustment device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram of an exemplary image production device in accordance with one possible embodiment of the disclosure; 
         FIG. 2  is an exemplary block diagram of the image production device in accordance with one possible embodiment of the disclosure; 
         FIG. 3  is an exemplary diagram of the nip print scanning environment in accordance with one possible embodiment of the disclosure; 
         FIG. 4  is an exemplary nip print image in accordance with one possible embodiment of the disclosure; and 
         FIG. 5  is a flowchart of an exemplary a nip width adjustment process in accordance with one possible embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Aspects of the embodiments disclosed herein relate to a method for automatically adjusting nip width based on a scanned nip print image on UV-sensitive media in an image production device, as well as corresponding apparatus and computer-readable medium. 
     The disclosed embodiments may include a method for automatically adjusting nip width based on a scanned nip print image on ultraviolet (UV)-sensitive media in an image production device. The method may include receiving a signal to generate a nip print, automatically inserting a sheet of UV-sensitive media into a fuser nip in the image production device, pausing the sheet of UV-sensitive media in the fuser nip for a predetermined time period, illuminating the UV-sensitive media with ultraviolet light to generate a nip print, scanning the generated nip print, determining if a nip width adjustment is required based on the scanned nip print, and if it is determined that a nip width adjustment is required based on the scanned nip print, adjusting the nip width using a nip width adjustment device. 
     The disclosed embodiments may further include an image production device that may include a feeder section that feeds media sheets to produce images in the image production device, a nip print scanner that scans a nip print, one or more ultraviolet lighting devices that illuminate a nip print with ultraviolet light, a nip print generator that receives a signal to generate a nip print, sends a signal to the feeder section to automatically insert a sheet of ultraviolet (UV)-sensitive media into a fuser nip in the image production device, the fuser nip being an intersection of the fuser roll and the pressure roll, pauses the sheet of UV-sensitive media in the fuser nip for a predetermined time period, illuminates the UV-sensitive media with ultraviolet light from the one or more ultraviolet lighting devices to generate a nip print, and sends a signal to the nip print scanner to scan the generated nip print, and a nip width adjustment unit that determines if a nip width adjustment is required based on the scanned nip print, the nip width being the distance of an arc length created by an intersection of the fuser roll and the pressure roll, and if the nip print adjustment unit determines that a nip width adjustment is required based on the scanned nip print, the nip print adjustment unit adjusts the nip width using a nip width adjustment device. 
     The disclosed embodiments may further include a computer-readable medium storing instructions for controlling a computing device for automatically adjusting nip width based on a scanned nip print image on ultraviolet (UV)-sensitive media in an image production device. The instructions may include receiving a signal to generate a nip print, automatically inserting a sheet of UV-sensitive media into a fuser nip in the image production device, pausing the sheet of UV-sensitive media in the fuser nip for a predetermined time period, illuminating the UV-sensitive media with ultraviolet light to generate a nip print, scanning the generated nip print, determining if a nip width adjustment is required based on the scanned nip print, and if it is determined that a nip width adjustment is required based on the scanned nip print, adjusting the nip width using a nip width adjustment device. 
     The disclosed embodiments may concern a method and apparatus for automatically adjusting nip width based on a scanned nip print image on ultraviolet (UV)-sensitive media (such as erasable paper) in an image production device. The UV-sensitive paper may be coated with photosensitive chemicals which turn dark upon hitting UV light emitted from one or more UV light source, such as a thin bar. The coating molecules may readjust themselves within 24 hours to their original form to delete the image. The paper may also be erased instantly by applying heat using a lamp, heated rollers, etc. To measure nip width, a sheet of UV-sensitive paper may be automatically loaded in the fuser nip. The UV-sensitive paper may be illuminated with UV light both in the pre-nip and post-nip regions. The nip width may then be determined by the width of the area that did not image. 
     This process may be automated with an in-line or external scanner or simple optical encoder. Once the nip width is determined, the nip width information can be fed back to a nip width adjustment unit to control the nip load. The ultraviolet lighting devices may be very small, so they can be mounted in the fuser. The flash time and intensity may be tuned to produce a readable and clear cut image. The fuser rotation may slow down during this process, if necessary. This approach may also be extensible to the measurement of transfer system nips in bias belt, bias roll, or intermediate belt configurations. Nip width is a key parameter that can be measured by this process and adjust automatically to compensate for transfer variability due primarily to paper and environmental conditions. Lastly, this technique may be very effective in measuring nip width variation from inboard to outboard for both fusing and transfer subsystems. 
     Compared to the existing nip width adjustment processes, the process described in the disclosed embodiments would be more precise, cleaner, and faster. In addition, since UV-sensitive paper is cheap and reusable, the process is also economic and “green.” The UV-sensitive paper can be made in different paper weights and paper stiffness characteristics to match paper being run on the machine or to bracket the ends of the thickness range. This process may allow the nip width measurement to be tailored to the type of paper being run on the machine to enable more accurate nip width settings for different substrates. Note also, that the heated fuser roll may be used erase the image in the nip after nip width measurement has been made. 
     The process may use the existing simplex or duplex loop, for example. An automatic nip width adjustment device may move the fuser and pressure roll center to center distance either by lead screw or cam adjustment, for example. Independent inboard and outboard edge measurements may be taken to ensure uniformity. 
     The nip width measurement process may be required after each fuser roll change and at periodic intervals between jobs, for example. This process may reduce fuser roll edge wear rate by reducing the mean and variability of the nip width. The process may also provide an advantage over the manual procedure because of its accuracy and automated operation, which may occur during continuous motion, for example. 
     If integrated into the fuser roll change procedure, a prompt requiring the nip print scanning process may appear on the Print Station Interface Platform (PSIP) Graphical Use Interface (GUI). Thus, the operator may be more likely to complete the nip setup routine after each roll change or at designated intervals. 
       FIG. 1  is an exemplary diagram of an image production device  100  in accordance with one possible embodiment of the disclosure. The image production device  100  may be any device that may be capable of making image production documents (e.g., printed documents, copies, etc.) including a copier, a printer, a facsimile device, and a multi-function device (MFD), for example. 
     The image production device  100  may include an image production section  120 , which includes hardware by which image signals are used to create a desired image, as well as a feeder section  110 , which stores and dispenses sheets on which images are to be printed, and an output section  130 , which may include hardware for stacking, folding, stapling, binding, etc., prints which are output from the marking engine. If the printer is also operable as a copier, the printer further includes a document feeder  140 , which operates to convert signals from light reflected from original hard-copy image into digital signals, which are in turn processed to create copies with the image production section  120 . The image production device  100  may also include a local user interface  150  for controlling its operations, although another source of image data and instructions may include any number of computers to which the printer is connected via a network. 
     With reference to feeder section  110 , the module may include any number of trays  160 , each of which may store a media stack or print sheets (“media”) of a predetermined type (size, weight, color, coating, transparency, etc.) and includes a feeder to dispense one of the sheets therein as instructed. Certain types of media may require special handling in order to be dispensed properly. For example, heavier or larger media may desirably be drawn from a media stack by use of an air knife, fluffer, vacuum grip or other application (not shown in the Figure) of air pressure toward the top sheet or sheets in a media stack. Certain types of coated media are advantageously drawn from a media stack by the use of an application of heat, such as by a stream of hot air (not shown in the Figure). Sheets of media drawn from a media stack on a selected tray  160  may then be moved to the image production section  120  to receive one or more images thereon. 
     In this embodiment, the image production section  120  is shown to be a monochrome xerographic type engine, although other types of engines, such as color xerographic, ionographic, or ink-jet may be used. In  FIG. 1 , the image production section  120  may include a photoreceptor which may be in the form of a rotatable belt. The photoreceptor may be called a “rotatable image receptor,” meaning any rotatable structure such as a drum or belt which can temporarily retain one or more images for printing. Such an image receptor can comprise, by way of example and not limitation, a photoreceptor, or an intermediate member for retaining one or more marking material layers for subsequent transfer to a sheet, such as in a color xerographic, offset, or ink-jet printing apparatus. 
     The photoreceptor may be entrained on a number of rollers, and a number of stations familiar in the art of xerography are placed suitably around the photoreceptor, such as a charging station, imaging station, development station, and transfer station. In this embodiment, the imaging station is in the form of a laser-based raster output scanner, of a design familiar in the art of “laser printing,” in which a narrow laser beam scans successive scan lines oriented perpendicular to the process direction of the rotating photoreceptor. The laser may be turned on and off to selectably discharge small areas on the moving photoreceptor according to image data to yield an electrostatic latent image, which is developed with marking material at development station and transferred to a sheet at transfer station. 
     A sheet having received an image in this way is subsequently moved through fuser section that may include a fuser roll  170  and a pressure roll  180 , of a general design known in the art, and the heat and pressure from the fuser roll  170  causes the marking material image to become substantially permanent on the sheet. The fuser nip  190  is shown as the arc distance between the fuser roll  170  and the pressure roll  180 . The sheet once printed, may then be moved to output section  130 , where it may be collated, stapled, folded, etc., with other media sheets in a manner familiar in the art. 
     Although the above description is directed toward a fuser used in xerographic printing, it will be understood that the teachings and claims herein can be applied to any treatment of marking material on a medium. For example, the marking material may comprise liquid or gel ink, and/or heat- or radiation-curable ink; and/or the medium itself may have certain requirements, such as temperature, for successful printing. The heat, pressure and other conditions required for treatment of the ink on the medium in a given embodiment may be different from those suitable for xerographic fusing. 
     The ultraviolet lighting devices  185  may be any devices that emit ultraviolet light. The ultraviolet lighting devices  185  may be small enough in size to fit into the fuser area and one or more of the devices  185  may be used to illuminate the UV-sensitive media. The ultraviolet lighting devices  185  may also be used to cure ink used in certain printers. In this manner, simultaneously with the mechanical pressure applied at the nip, radiant UV energy from the ultraviolet lighting devices  185  may be applied to the ink for chemical curing of the ink on the media as it passes through the nip. 
     The nip print scanner  195  may be any scanner that has the ability to scan nip prints in the image production device  100  and provide the resulting nip width information from the scanned nip print as feedback to determine if nip width adjustments need to be made. While the nip print scanner  195  is shown as an in-line scanner, one of skill in the art will appreciate that other scanners may be used, such as external scanners. For example, the document scanning device on the image production device  100  may be used to scan the nip print. 
       FIG. 2  is an exemplary block diagram of the image production device  100  in accordance with one possible embodiment of the disclosure. The image production device  100  may include a bus  210 , a processor  220 , a memory  230 , a read only memory ROM)  240 , a nip width adjustment unit  250 , a nip print generator  270 , a feeder section  110 , an output section  130 , a user interface  150 , a communication interface  260 , an image production section  120 , one or more ultraviolet lighting devices  185 , and a nip print scanner  195 . Bus  210  may permit communication among the components of the image production device  100 . 
     Processor  220  may include at least one conventional processor or microprocessor that interprets and executes instructions. Memory  230  may be a random access memory (RAM) or another type of dynamic storage device that stores information and instructions for execution by processor  220 . Memory  230  may also include a read-only memory ROM) which may include a conventional ROM device or another type of static storage device that stores static information and instructions for processor  220 . 
     Communication interface  260  may include any mechanism that facilitates communication via a network. For example, communication interface  260  may include a modem. Alternatively, communication interface  260  may include other mechanisms for assisting in communications with other devices and/or systems. 
     ROM  240  may include a conventional ROM device or another type of static storage device that stores static information and instructions for processor  220 . A storage device may augment the ROM and may include any type of storage media, such as, for example, magnetic or optical recording media and its corresponding drive. 
     User interface  150  may include one or more conventional mechanisms that permit a user to input information to and interact with the image production unit  100 , such as a keyboard, a display, a mouse, a pen, a voice recognition device, touchpad, buttons, etc., for example. Feeder section  110  may be any mechanism that may feed media sheets to the image production section  120  to produce imaged media. The image production section  120  may include an image printing and/or copying section, a scanner, a fuser, etc., for example. Output section  130  may include one or more conventional mechanisms that output image production documents to the user, including output trays, output paths, finishing section, etc., for example. As stated above, the nip print scanner  195  may be any scanner that has the ability to scan nip prints and provide them to the nip width adjustment unit  250  for a determination as to whether a nip width adjustment is necessary. 
     The image production device  100  may perform such functions in response to processor  220  by executing sequences of instructions contained in a computer-readable medium, such as, for example, memory  230 . Such instructions may be read into memory  230  from another computer-readable medium, such as a storage device or from a separate device via communication interface  260 . 
     The image production device  100  illustrated in  FIGS. 1-2  and the related discussion are intended to provide a brief, general description of a suitable communication and processing environment in which the disclosure may be implemented. Although not required, the disclosure will be described, at least in part, in the general context of computer-executable instructions, such as program modules, being executed by the image production device  100 , such as a communication server, communications switch, communications router, or general purpose computer, for example. 
     Generally, program modules include routine programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Moreover, those skilled in the art will appreciate that other embodiments of the disclosure may be practiced in communication network environments with many types of communication equipment and computer system configurations, including personal computers, hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, and the like. 
       FIG. 3  is an exemplary diagram of the nip print scanning environment  300  in accordance with one possible embodiment of the disclosure. The nip print scanning environment  300  may be found in the image production section  120  and may include the fuser roll  170 , the pressure roll  180 , the fuser nip  190 , one or more ultraviolet (UV) lighting devices  185 , the nip print scanner  195 , UV-sensitive media (such as erasable paper)  320 , and a nip width adjustment device  310 . 
     When dictated by the operator pressing a soft or hard button at the user interface  150 , a sheet of UV-sensitive media  320  may be fed automatically by the feeder section  130  into the fuser nip  190 . If integrated into the fuser roll change procedure, a prompt requiring the nip print scanning process may appear on the Print Station Interface Platform (PSIP) Graphical User Interface (GUI). However, the nip print generator  270  may automatically schedule nip prints to be generated at a fuser roll change or automatically, for example. The UV-sensitive media sheet may be paused in the fuser nip  190  for less than 5 seconds preferably around 1 second). The one or more ultraviolet lighting devices  185  may illuminate the UV-sensitive media  320  for less than 5 seconds preferably around 1 second), or as long as necessary to allow the nip print to be generated. The nip print may then be jettisoned through the fuser and passed through the nip print scanner  195  to be scanned. 
     An example of a nip print image  400  using this process is shown in  FIG. 4 . One can see in the image where the band  410  on the UV-sensitive media  320  is lighter than the rest of the media. This band  410  represents an area not illuminated by the ultraviolet lighting devices  185  while the UV-sensitive media  320  that was in the nip. As such, the band  410  may represent the nip width. 
     The nip print  400  may then be jettisoned toward the nip print scanner  195 . The nip print scanner  195  may be located in the path after the nip and may be positioned in the simplex (single side) or the duplex (double side) media sheet path. The nip print  400  may then scanned by the nip print scanner  195  and the information may be provided to the nip width adjustment unit  250  to determine whether the nip width needs to be adjusted. The nip print  400  may be scanned on each edge of the fuser roll  170 , such as the inboard and outboard edges, for example. 
     The nip print scanning process may be scheduled by an operator or in the factory such that a nip print  400  may be generated and scanned automatically upon fuser roll replacement or on a periodic basis, for example. 
     If the nip print scanning process dictates, the nip width adjustment unit  250  may use the nip width adjustment device  310  to change the nip width by adjusting the distance between the fuser roll  170  and the pressure roll  180 . The nip width adjustment device  310  shown in  FIG. 3  may be a rotary cam-type adjustment device that automatically raises or lowers the pressure roll  180  to adjust the pressure exerted upon the fuser roll  170  by the pressure roll  180  and hence, adjust the nip width. Note that while the nip width adjustment device  310  is illustrated to be within the pressure roll  180  in  FIG. 3 , alternative arrangements may be used without limitation, including a cam and cam follower device, shim adjustment device, or a spring adjustment device, for example. In addition, the nip width adjustment device  310  may also be installed on the fuser roll  170 , for example. 
     Upon appropriate rotation of nip width adjustment device  310  (the rotary cam), the position of the pressure roll is adjusted. Thus, appropriate rotation of the nip width adjustment device  310  (the rotary cam) can move the pressure roll  180  toward the fuser roll  170 , thereby increasing the amount of pressure exerted by the pressure roll  180  upon the fuser roll  170 . Control of the nip width adjustment device  310  by the nip width adjustment unit  250  may be implemented by any means well known in the art. 
     The operation of components of the nip print generator  270 , the nip width adjustment unit  250 , the nip print scanner  195 , and the nip width adjustment process will be discussed in relation to the flowchart in  FIG. 5 . 
       FIG. 5  is a flowchart of an exemplary fuser roll adjustment process in accordance with one possible embodiment of the disclosure. The method begins at  5100 , and continues to  5200  where the nip print generator  270  may receive a signal to generate a nip print  400 . The signal may be received from the user interface  150  after being initiated by an operator, for example. Alternatively, the signal to generate the nip print  400  may be performed by the image production device  100  automatically upon either fuser roll replacement or on a periodic basis, for example. 
     At step  5300 , the nip print generator  270  may signal the feeder section  110  to automatically insert a sheet of UV-sensitive media  320  into a fuser nip  190  in the image production device  100 . At step  5400 , the nip print generator  270  may pause the UV-sensitive media  320  in the fuser nip  190  for a predetermined time period. The predetermined time period may be less than 5 seconds, for example. 
     At step  5500 , the nip print generator  270  may illuminate the UV-sensitive media  320  with ultraviolet light from the ultraviolet lighting devices  185  to generate a nip print  400 . The nip width may be represented by an area not illuminated by the ultraviolet lighting devices  185  while the UV-sensitive media  320  that was in the fuser nip  190 . At step  5600 , the nip print generator  270  may send a signal to the nip print scanner  195  to scan the nip print  400 . At step  5700 , the nip width adjustment unit  250  may determine if a nip width adjustment is required based on the scanned nip print  400 . If the nip width adjustment unit  250  determines that a nip width adjustment is not required based on the scanned nip print  400 , the process may then go to step  5900  and end. However, if at step  5700 , the nip print adjustment unit  250  determines that a nip width adjustment is required based on the scanned nip print  400 , then at step  5800 , the nip print adjustment unit  250  adjusts the nip width using the nip width adjustment device  310 . The process may then go to step  5900  and end. 
     Embodiments as disclosed herein may also include computer-readable media for carrying or having computer-executable instructions or data structures stored thereon. Such computer-readable media can be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code means in the form of computer-executable instructions or data structures. When information is transferred or provided over a network or another communications connection (either hardwired, wireless, or combination thereof to a computer, the computer properly views the connection as a computer-readable medium. Thus, any such connection is properly termed a computer-readable medium. Combinations of the above should also be included within the scope of the computer-readable media. 
     Computer-executable instructions include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions. Computer-executable instructions also include program modules that are executed by computers in stand-alone or network environments. Generally, program modules include routines, programs, objects, components, and data structures, and the like that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of the program code means for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described therein. It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.