Patent Publication Number: US-8116649-B2

Title: Apparatus and method for adjusting cleaning station operation in a printing apparatus

Description:
BACKGROUND 
     Disclosed herein is an apparatus and method that adjusts cleaning station operation in a printing apparatus. 
     Presently, image output devices, such as printers, multifunction media devices, xerographic machines, ink jet printers, and other devices produce images on media sheets, such as paper, substrates, transparencies, plastic, cardboard, or other media sheets. To produce an image, a photoreceptor transfers marking material, such as toner, ink jet ink, or other marking material, to a media sheet to create a latent image on the media sheet. A fuser assembly then affixes or fuses the latent image to the media sheet by applying heat and/or pressure to the media sheet. After the image is affixed to the media sheet, a cleaning station uses a rotating cleaning brush to clean residual marking material and other debris off the photoreceptor. 
     Unfortunately, photoreceptor cleaning is abrasive and erodes the photoreceptor surface and performance over time. Current cleaning implementations are designed for stress cases involving high density solids and lines of significant length in the photoreceptor process direction. Thus, current cleaning implementations involve higher biases and faster cleaning brush revolutions per minute (RPM&#39;s) which can adversely impact both the system reliability from the higher bias and the print quality from faster RPM&#39;s. Current cleaning implementations do not adjust cleaning station operation based on the type of image on the photoreceptor. 
     Thus, there is a need for an apparatus and method that adjusts cleaning station operation in a printing apparatus. 
     SUMMARY 
     An apparatus and method that adjusts cleaning station operation in a printing apparatus is disclosed. The apparatus can include a charge receptor movable in a process direction, where the charge receptor can have a main surface. The apparatus can include a charger configured to generate a charge on the charge receptor and an image generator configured to generate an image on the charge receptor. The apparatus can include a cleaning station coupled to the charge receptor. The cleaning station can include a cleaning brush coupled to the main surface of the charge receptor. The cleaning station can be configured to clean the main surface of the charge receptor. The apparatus can include a controller coupled to the cleaning station. The controller can be configured to determine a type of image generated on the charge receptor and can be configured to adjust cleaning parameters of operation of the cleaning station based on the type of image generated on the charge receptor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to describe the manner in which advantages and features of the disclosure can be obtained, a more particular description of the disclosure briefly described above will be rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the disclosure and are not therefore to be considered to be limiting of its scope, the disclosure will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1  is an exemplary illustration of an apparatus according to a possible embodiment; 
         FIG. 2  is an exemplary flowchart of a method according to a possible embodiment; and 
         FIG. 3  is an exemplary illustration of a printing apparatus according to a possible embodiment. 
         FIG. 4  is an exemplary illustration of an image that can be printed on a media sheet as the media sheet moves in the process direction according to a possible embodiment; and 
         FIG. 5  is an exemplary illustration of an image that can be printed on a media sheet as the media sheet moves in the process direction according to a possible embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments include an apparatus for adjusting cleaning station operation in a printing apparatus. The apparatus can include a charge receptor movable in a process direction, where the charge receptor can have a main surface. The apparatus can include a charger configured to generate a charge on the charge receptor and an image generator configured to generate an image on the charge receptor. The apparatus can include a cleaning station coupled to the charge receptor. The cleaning station can include a cleaning brush coupled to the main surface of the charge receptor. The cleaning station can be configured to clean the main surface of the charge receptor. The apparatus can include a controller coupled to the cleaning station. The controller can be configured to determine a type of image generated on the charge receptor and can be configured to adjust cleaning parameters of operation of the cleaning station based on the type of image generated on the charge receptor. 
     The embodiments further include a method of for adjusting cleaning station operation in a printing apparatus having a charge receptor movable in a process direction, the charge receptor having a main surface, the apparatus also having a charger, an image generator, and a cleaning station coupled to the charge receptor, the cleaning station including a cleaning brush coupled to the main surface of the charge receptor, the apparatus also having a controller coupled to the cleaning station. The method can include generating a charge, using the charger, on the charge receptor. The method can include generating an image, using the image generator, on the charge receptor. The method can include cleaning, using the cleaning brush, the main surface of the charge receptor. The method can include determining, using the controller, a type of image generated on the charge receptor. The method can include adjusting, using the controller, cleaning parameters of operation of the cleaning station based on the type of image generated on the charge receptor. 
     The embodiments further include an apparatus for adjusting cleaning station operation in a printing apparatus. The apparatus can include a charge receptor movable in a process direction, where the charge receptor can have a main surface. The apparatus can include a charger configured to generate a charge on the charge receptor. The apparatus can include an image generator configured to generate an image on the charge receptor. The apparatus can include a cleaning station coupled to the charge receptor. The cleaning station can include a cleaning brush coupled to the main surface of the charge receptor. The cleaning station can be configured to clean the main surface of the charge receptor. The apparatus can include a sensor configured to sense an image generated on the charge receptor. The apparatus can include a controller coupled to the cleaning station. The controller can be configured to determine a type of image generated on the charge receptor based on the sensed image and can be configured to adjust cleaning parameters of operation of the cleaning brush based on the type of image generated on the charge receptor. The apparatus can include a transfer unit coupled to the charge receptor. The transfer unit can be configured to transfer the image to media. 
       FIG. 1  is an exemplary illustration of an apparatus  100 , such as an electrostatographic printing apparatus, a xerographic printing apparatus, an ink jet printing apparatus, or any other apparatus that generates an image on media. The apparatus  100  may also be part of a printer, a multifunction media device, a xerographic machine, a laser printer, an ink jet printer, or any other device that generates an image on media. The apparatus  100  can include a media transport  130  that can transport media  135 , such as paper, plastic, stickers, or other media. The apparatus  100  can include a charge receptor  110  movable in a process direction P. The charge receptor  110  can have a main surface  111 . The charge receptor  110  can be a photoreceptor. The charge receptor  110  can also be part of a marking system including a photoreceptor, where the photoreceptor can have a photoreceptor charge transport surface  111 . For example, a photoreceptor can be a belt or drum and can include a photoreceptor charge transport surface for forming electrostatic images thereon. A photoreceptor can rotate in a process direction P and can generate an image on the media  135 . 
     The apparatus  100  can include a charger  140  configured to generate a charge on the charge receptor  110 . The charger  140  can be a scorotron, a charge roll, or any other electric field generation device, that can apply a voltage to a photoconductor  110 . For example, a scorotron  140  can include a scorotron shield  142 , a scorotron charging grid  144 , and a scorotron wire or pin array  146  located on an opposite side of the scorotron charging grid  144  from the photoconductor  110 . The scorotron pin array  146  can be configured to generate an electric field. The scorotron charging grid  144  and the scorotron pin array  146  can be configured to generate a surface potential on the photoconductor  110 . In a more detailed operation, the charger  140  can charge the charge receptor  110  surface by imparting an electrostatic charge on the surface of the charge receptor  110  as the charge receptor  110  rotates in the process direction P. 
     The apparatus  100  can include an image generator  112  configured to generate an image on the charge receptor  110 . The image generator  112  can be a raster output scanner, such as a laser source, a Light Emitting Diode (LED) bar, or other relevant device, that can discharge selected portions of the charge receptor  110  in a configuration corresponding to a desired image to be printed. For example, a raster output scanner can discharge a latent image to a more positive voltage. As a further example, the charger  112  can be a raster output scanner that can include a laser source  114  and a rotatable mirror  116 , which can act together to discharge certain areas of the surface of the charge receptor  110  according to a desired image to be printed. Other elements can be used instead of a laser source  114  to selectively discharge the charge-retentive surface  111 , such as an LED bar, a light-lens system, or other elements that can discharge a charge-retentive surface. The laser source  114  can be modulated in accordance with digital image data fed into it, and the rotatable mirror  116  can cause the modulated beam from the laser source  114  to move in a fast-scan direction perpendicular to the process direction P of the charge receptor  110 . 
     The apparatus  100  can include a fuser  122  that can transfer the image on the charge receptor to the media  135 . For example, the fuser  122  can cause marking material, such as toner or ink, to melt or fuse into the media  135  to create a permanent image on the media  135 . The apparatus  100  can include a cleaning station  124  coupled to the charge receptor  110 . The cleaning station  124  can be configured to clean the main surface  111  of the charge receptor  110 . The cleaning station  124  can include a cleaning brush  125  coupled to the main surface  111  of the charge receptor  110 . For example, the cleaning device  124  can clean the charge receptor  110  using an electric field generated between the fibers of the brush  125  and residual toner on the charge receptor surface  111  after an image is transferred to the media  135 . 
     The apparatus  100  can include a controller  150  coupled to the cleaning station  124 . The controller  150  can also be coupled to the charge device  140 , the charge receptor  110 , and other elements of the apparatus  100  and can control operations of the apparatus  100 . The controller  150  can be configured to determine a type of image generated on the charge receptor  110  and can be configured to adjust cleaning parameters of operation of the cleaning station  124  based on the type of image generated on the charge receptor  110 . For example, the controller  150  can preview the image generated on the charge receptor  110  and can determine a type of image generated on the charge receptor  110  based on the previewed image. As a further example, the type of image can be based on density of marking material, such as mass per area of the marking material in the process direction P, can be based on a length of dense lines in the process direction P, can be a text image, can be a picture image, can be a combination of text and graphics, can be a lubrication patch, or can be any other type of image. The type of image can also be based on the image structure of the image, such as the composition of lines on the image, the repetition vs. randomness of lines on the image, or other toner images. For example, half tones and text can be less dense than solids and recurring lines. To elaborate, text can be more random than a recurring line and less prone to create a ghost image. Such information about the type of image can be used to adjust cleaning parameters of operation of the cleaning station  124 . 
     According to one embodiment, the controller  150  can be configured to determine type of image generated on the charge receptor  110  by determining a density of marking material of the image and can be configured to adjust cleaning parameters of operation of the cleaning station  124  based on the density of marking material of the image. As another example, the controller  150  can be configured to determine type of image generated on the charge receptor  110  by determining an image structure of the image and can be configured to adjust cleaning parameters of operation of the cleaning station  124  based on the image structure of the image. 
     The controller  150  can adjust cleaning parameters of operation of the cleaning station  124  by adjusting a revolution speed of the cleaning brush  125  based on the type of image. The controller can adjust the revolution speed of the cleaning brush  125  by lowering the cleaning brush revolution speed for a lower density of marking material of the image and by raising the cleaning brush revolution speed for a higher density of marking material of the image. For example, the controller  150  can adjust the revolution speed of the cleaning brush  125  by raising the revolution speed for repetitive stresses and by lowering the revolution speed for less repetitive stresses. 
     The controller  150  can be configured to determine stress on the cleaning brush  125  based on the type of image generated on the charge receptor  110  and can be configured to adjust cleaning parameters of operation of the cleaning station  124  based on the stress on the cleaning brush  125 . For example, stress on the cleaning brush  125  can be based on high density of marking material, such as toner, ink, or other marking material. Also, stress on the cleaning brush  125  can be related to stress on the charge receptor  110  from the cleaning brush  125 . The controller  150  can be configured to adjust cleaning parameters of operation of the cleaning station  124  by lowering a bias of the cleaning brush  125  for less stressful conditions and by raising the bias of the cleaning brush  125  for more stressful conditions based on the stress on the cleaning brush  125 . For example, failure modes can occur from higher bias of the cleaning brush  125 , such as from arcing in the device. Less energy, such as based on the cleaning brush voltage, can provide higher reliability of a printing apparatus image generation subsystem. 
     As a further example, the controller  150  can process a digital image to operate the image generator  112  to generate the image on the charge receptor  110 . The controller  150  can preview the type of image generated on the charge receptor  110  based on information about the processed image. For example, the controller  150  can include a digital front end that can receive image data for printing an image. The controller  150  can analyze the image data to determine the density of marking material that can be used to generate the image on the charge receptor  110 . The controller  150  can adjust parameters of operation of the cleaning station  124  based on the density of marking material and/or based on other information from the image data. 
     The apparatus  100  can include a sensor  160  configured to sense an image generated on the charge receptor  110 . The sensor  160  can be coupled to the controller  150 . The controller  150  can determine a type of image generated on the charge receptor  110  based on the sensed image. The sensor  160  can be a full width array sensor, a toner concentration (TC) sensor, a tribo sensor, or any other sensor useful to sense an image generated on the charge receptor  110 . For example, an electrostatic sensor can be used to detect the toner concentration and/or a tribo sensor can detect a charge on the charge receptor  110 . As a further example, existing sensors in a printing apparatus can be repositioned to determine the image structure and/or density. As an alternate example, one or more sensors can be added to detect a type of image on the charge receptor. Existing or additional sensors can not only incorporate existing functions of process controls, they can also use existing structures and/or can be modular for an enhanced process control strategy and efficient cleaning mechanism. 
     The apparatus  100  can include a development unit  118  coupled to the charge receptor  110 . The development unit  118  can be configured to develop the image on the charge receptor  110 . For example, after certain areas of the charge receptor  110  are discharged by the laser source  114 , a developer unit  118  can develop an exposed latent image by applying a voltage bias using the developer unit  118 . The developer unit  118  can cause a supply of marking material, such as dry toner or ink, to contact or otherwise approach the exposed latent image on the surface of the charge receptor  110 . 
     The apparatus  100  can include a transfer unit  120  coupled to the charge receptor  110 . The transfer unit  120  can be configured to transfer the developed image to the media  135 . For example, the transfer unit  120  can cause the toner adhering to the charge receptor  110  to be electrically transferred to the media  135 . 
     The sensor  160  can be located between the development unit  118  and the transfer unit  120 . For example, the sensor  160  can be located after the development unit  118  and before the transfer unit  120  based on the process direction P of the charge receptor  110 . The sensor  160  can detect the full image on the charge receptor  110  before it is transferred to a media sheet and then the controller  150  can determine exactly what is being transferred to the media sheet from the charge receptor  110 . 
     The controller  150  also can be configured to determine the type of image is a lubrication patch and can be configured to adjust cleaning parameters of operation of the cleaning station  124  to stop cleaning based on the type of image being a lubrication patch. 
     According to a related embodiment, the apparatus  100  can include a charge receptor  110  movable in a process direction P. The charge receptor  110  can have a main surface  111 . The apparatus  100  can include a charger  140  configured to generate a charge on the charge receptor  110 . The apparatus  100  can include an image generator  112  configured to generate an image on the charge receptor  110 . The apparatus  100  can include a cleaning station  124  coupled to the charge receptor  110 . The cleaning station  124  can be configured to clean the main surface  111  of the charge receptor  110 . The cleaning station  124  can include a cleaning brush  125  coupled to the main surface  111  of the charge receptor  110 . The apparatus  100  can include a sensor  160  configured to sense an image generated on the charge receptor  110 . The apparatus  100  can include a controller  150  coupled to the cleaning station  124 . The controller  150  can be configured to determine a type of image generated on the charge receptor  110  based on the sensed image. The controller  150  can also be configured to adjust cleaning parameters of operation of the cleaning brush  125  based on the type of image generated on the charge receptor  110 . The apparatus  100  can include a transfer unit  120  coupled to the charge receptor  110 . The transfer unit  120  can be configured to transfer the image to media  135 . 
     The apparatus  100  can include a development unit  118  coupled to the charge receptor  110 . The development unit  118  can be configured to develop the image on the charge receptor  110 . The transfer unit  120  can be configured to transfer the developed image to media  135 . The sensor  160  can be located between the development unit  120  and the transfer unit  118 . 
       FIG. 2  illustrates an exemplary flowchart  200  of a method in an electrostatographic printing apparatus, such as the apparatus  100 . The apparatus can include a charge receptor movable in a process direction. The charge receptor can have a main surface. The apparatus can include a charger, an image generator, and a cleaning station coupled to the charge receptor. The cleaning station can include a cleaning brush coupled to the main surface of the charge receptor. The apparatus can include a sensor. The apparatus can include a development unit coupled to the charge receptor, where the development unit can be configured to develop an image on the charge receptor. The apparatus can include a transfer unit coupled to the charge receptor, where the transfer unit can be configured to transfer the developed image to media. The sensor can be located between the development unit and the transfer unit. The apparatus can include a controller coupled to the cleaning station. The method starts at  210 . At  220 , the charger can generate a charge on the charge receptor. At  230 , the image generator can generate an image on the charge receptor. At  240 , the sensor can sense an image generated on the charge receptor. At  250 , the controller can determine a type of image generated on the charge receptor. For example, the controller can preview the image generated on the charge receptor and can determine the type of image generated on the charge receptor based on the previewed image. As a further example, the controller can determine a type of image generated on the charge receptor by determining a density of marking material of the image. The controller can also determine the type of image generated on the charge receptor by determining an image structure of the image. When determining the type of image, the controller can determine stress on the cleaning brush based on the type of image generated on the charge receptor. The controller can also determine a type of image generated on the charge receptor based on the sensed image. 
     At  260 , the controller can adjust cleaning parameters of operation of the cleaning station based on the type of image generated on the charge receptor. For example, the controller can adjust cleaning parameters of operation of the cleaning station based on the density of marking material of the image. The controller can also adjust cleaning parameters of operation of the cleaning station based on the image structure of the image. The controller can also adjust cleaning parameters of operation of the cleaning station by adjusting a revolution speed of the cleaning brush based on the type of image. The controller can adjust a revolution speed of the cleaning brush by lowering the cleaning brush revolution speed for lower density of marking material of the image and raising the cleaning brush revolution speed for higher density of marking material of the image. The controller can also adjust cleaning parameters of operation of the cleaning station based on the stress on the cleaning brush. The controller can also adjust cleaning parameters of operation of the cleaning station by lowering a bias of the cleaning brush for less stressful conditions and by raising the bias of the cleaning brush for more stressful conditions based on the stress on the cleaning brush. At  270 , the cleaning brush can clean the main surface of the charge receptor. At  280 , the method can end. 
       FIG. 3  illustrates an exemplary printing apparatus  300 . As used herein, the term “printing apparatus” encompasses any apparatus, such as a digital copier, bookmaking machine, multifunction machine, and other printing devices that perform a print outputting function for any purpose. The printing apparatus  300  can be used to produce prints on various media, such as coated, uncoated, previously marked, or plain paper sheets. The media can have various sizes and weights. In some embodiments, the printing apparatus  300  can have a modular construction. As shown, the printing apparatus  300  can include at least one media feeder module  302 , a printer module  306  adjacent the media feeder module  302 , an inverter module  314  adjacent the printer module  306 , and at least one stacker module  316  adjacent the inverter module  314 . 
     In the printing apparatus  300 , the media feeder module  302  can be adapted to feed media  304  having various sizes, widths, lengths, and weights to the printer module  306 . The printer module  306  can include the apparatus  100 . In the printer module  306 , toner is transferred from an arrangement of developer stations  310  to a charged photoreceptor belt  307  to form toner images on the photoreceptor belt  307 . The toner images are transferred to the media  304  fed through a paper path. The media  304  are advanced through a fuser  312  adapted to fuse the toner images on the media  304 . The inverter module  314  manipulates the media  304  exiting the printer module  306  by either passing the media  304  through to the stacker module  316 , or by inverting and returning the media  304  to the printer module  306 . In the stacker module  316 , printed media are loaded onto stacker carts  317  to form stacks  320 . 
       FIG. 4  is an exemplary illustration of an image  400  that can be printed on a media sheet as the media sheet moves in the process direction  410  according to a possible embodiment. The image  400  can include halftone images and text that can place less stress on a cleaning brush. Thus, the bias and revolution speed of a cleaning brush can be reduced when cleaning a charge receptor that produced the image  400 . 
       FIG. 5  is an exemplary illustration of an image  500  that can be printed on a media sheet as the media sheet moves in the process direction  510  according to a possible embodiment. The image  500  can include solids, lines in the process direction  510 , and repetitive solids or repetitive lines that can place more stress on a cleaning brush. Thus, the bias and revolution speed of a cleaning brush can be increased when cleaning a charge receptor that produced the image  500 . 
     Embodiments can provide for longer photoreceptor and cleaner brush life using optimal cleaner brush revolutions per minute (RPM) and bias as determined by a sensor, such as a full width inline sensor. A full width array sensor or a full width TC/tribo sensor can be used before transfer. A controller can determine the type of image and adjust cleaning parameters appropriately so that more aggressive cleaning can be implemented in the presence of high density lines and solids. Normal images, such as non-stressful half tones and text, may not require the same level of cleaning and corresponding lower cleaning brush RPM&#39;s and a lower bias can result in increased photoreceptor performance and improved system reliability. A sensor, such as a full width array sensor, can be located after development but before transfer so that a controller can determine the type of image and initiate stressed level cleaning parameters in the presence of stress images. The image stress factors for cleaning can include high density (mass/area) in the process direction. Depending upon the speed of the power supplies and the cleaner motor implemented, the bias and RPM can be switched fast enough for optimal control patch cleaning for improved productivity and/or for no cleaning for photoreceptor lubrication patches. The resulting improvement on both photoreceptor life and machine productivity can yield run cost benefits for a printing apparatus. 
     According to some embodiments, a sensor, such as a full width array sensor, can be implemented for real time feedback. Image density can be calculated in real time based on a TC/Tribo sensor and a development field of the printing apparatus. Also, cleaning parameters can be controlled based on image stress level. For example, when stress lines and solids are not present, a cleaner brush can run at substantially lower RPM and bias levels, which can increase both the cleaner brush and photoreceptor life. Depending upon types of images being run, the cleaner brush and photoreceptor life may be extended for up to 20% or more. 
     Embodiments may be implemented on a programmed processor. However, the embodiments may also be implemented on a general purpose or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an integrated circuit, a hardware electronic or logic circuit such as a discrete element circuit, a programmable logic device, or the like. In general, any device on which resides a finite state machine capable of implementing the embodiments may be used to implement the processor functions of this disclosure. 
     While this disclosure has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in the other embodiments. Also, all of the elements of each figure are not necessary for operation of the embodiments. For example, one of ordinary skill in the art of the embodiments would be enabled to make and use the teachings of the disclosure by simply employing the elements of the independent claims. Accordingly, the embodiments of the disclosure as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the disclosure. 
     In this document, relational terms such as “first,” “second,” and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, relational terms, such as “top,” “bottom,” “front,” “back,” “horizontal,” “vertical,” and the like may be used solely to distinguish a spatial orientation of elements relative to each other and without necessarily implying a spatial orientation relative to any other physical coordinate system. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “a,” “an,” or the like does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element. Also, the term “another” is defined as at least a second or more. The terms “including,” “having,” and the like, as used herein, are defined as “comprising.”