Patent Publication Number: US-2011074901-A1

Title: Image erasing apparatus and recording medium conveying method for image erasing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from the prior the U.S. Patent Application No. 61/226,631, filed on Jul. 17, 2009, and the prior the U.S. Patent Application No. 61/242,721, filed on Sep. 15, 2009 and the entire contents of which are incorporated herein by reference. 
    
    
     FIELD 
     An embodiment of the present invention relates to an image erasing apparatus configured to erase an image on a recording medium formed with an erasable developer and a recording medium conveying method for the image erasing apparatus. 
     BACKGROUND 
     In recent years, an image forming apparatus configured to form an image with an erasable developer and an erasing apparatus were introduced according to the demand for resource saving. The erasing apparatus erases an image by applying heat and light to a recording medium on which the image is formed with the erasable developer and erasing the developer. Therefore, the recording medium after the image is erased can be reused. 
     In some case, a recording medium on which an image is once formed is stapled or affixed with a tag or the like. Such a recording medium clogs a recording medium conveying path and causes a jam or damages the apparatus. 
     As measures against such a problem, there is proposed a technique for providing a detecting device configured to detect double feed and stopping conveyance of a recording medium when the double feed is detected. 
     There is also proposed a technique for providing, halfway in the recording medium conveying path, a sensor configured to detect the thickness of a recording medium and discharging the recording medium to the outside of the apparatus via the normal recording medium conveying path when the recording medium has unexpected thickness. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of the configuration of an image erasing apparatus; 
         FIG. 2  is a perspective view of a recording-medium collecting device; 
         FIG. 3  is a front view of the recording-medium collecting device viewed from a direction of an arrow A in  FIG. 1 ; 
         FIG. 4  is a diagram of a state of recording medium collecting operation by the recording-medium collecting device; 
         FIG. 5  is a diagram of recording medium collecting operation of a recording-medium collecting device according to a first application example; 
         FIG. 6  is a block diagram of the configuration of the image erasing apparatus; 
         FIG. 7  is a side view of the configuration of an image erasing apparatus according to a second application example; 
         FIG. 8  is a side view of the configuration of an image erasing apparatus according to a third application example; and 
         FIG. 9  is a side view of recording medium collecting operation of the image erasing apparatus according to the second application example. 
     
    
    
     DETAILED DESCRIPTION 
     Throughout this description, the embodiments and examples shown should be considered as exemplars, rather than limitations on the apparatus and methods of the present embodiment. 
     An image erasing apparatus and a recording medium conveying method for the image erasing apparatus according to an embodiment of the present invention are explained in detail below with reference to the accompanying drawings. 
     An image erasing apparatus  1  includes: a paper feeding tray configured to feed the recording medium; a sensor group including a double-feed detection sensor configured to detect double feed of the recording medium and a media sensor configured to detect thickness of the recording medium; a recording-medium conveying device configured to convey the recording medium; a collecting device provided in the recording-medium conveying device and configured to drop and collect the recording medium; a heating device configured to heat the recording medium to temperature equal to or higher than erasing temperature of a developer; a stacking device configured to stack the recording medium; and a control unit configured to cause, the recording-medium conveying device to collect the recording medium in the collecting device if the recording medium is judged non-conveyable on the basis of an output of the sensor group and cause the recording-medium conveying device to convey the recording medium in a direction of the heating device to erase an image if the recording medium is judged conveyable on the basis of an output of the sensor group. 
     Each of image erasing apparatuses  1 ,  2 , and  3  according to this embodiment include a paper feeding tray  11  configured to feed a recording medium, a sensor group including a double-feed detection sensor  13  configured to detect double feed of the recording medium and a media sensor  14  configured to detect the thickness of the recording medium, a collecting device configured to drop the recording medium in the vertical direction and collect the recording medium, and a recording-medium conveying device  20  configured to convey the recording medium. 
       FIG. 1  is a side view of the configuration of the image erasing apparatus  1  according to this embodiment. As shown in  FIG. 1 , the image erasing apparatus  1  includes the paper feeding tray  11  on which recording media to be subjected to image erasing are stacked, a paper feeding device  12  configured to extract a recording medium from the paper feeding tray  11 , the recording-medium conveying device  20  configured to convey the recording medium, and a sensor group including the double-feed detection sensor  13  configured to detect double feed of the recording medium and the media sensor  14  configured to detect the thickness of the recording medium. 
     The recording-medium conveying device  20  includes plural conveying rollers  20 A and a switching device  22  configured to switch a conveying path. 
     The double-feed detection sensor  13  includes an ultrasound generating device configured to emit ultrasound from one side of the recording medium to the recording medium and an ultrasound detecting device set on the other side of the recording medium and configured to detect the ultrasound. The double-feed detection sensor  13  outputs an electric signal on the basis of the detected ultrasound. The image erasing apparatus  1  determines presence or absence of double feed on the basis of the electric signal. 
     The media sensor  14  includes an arm displaced by the passage of the recording medium, a permanent magnet set in the arm, and a magnetic sensor configured to detect magnetism of the permanent magnet. The media sensor  14  outputs an electric signal corresponding to the thickness of the recording medium. The image erasing apparatus  1  determines the thickness of the recording medium on the basis of the electric signal. 
     The image erasing apparatus  1  includes, downstream in a recording medium conveyance direction of the sensor group, a recording-medium collecting device  30  and a collection box  31  configured to store a collected recording medium. 
     The recording-medium conveying device  20  is formed on a straight line from the paper feeding device  12  to the recording-medium collecting device  30 . The recording-medium conveying device  20  connecting the paper feeding device  12 , the sensor group, and the recording-medium collecting device  30  is formed on the straight line. The paper feeding device  12 , the sensor group, and the recording-medium collecting device  30  are arranged on the straight line. The image erasing apparatus  1  conveys the recording medium from the paper feeding device  12  to the recording-medium collecting device  30  without bending the recording medium. 
     The image erasing apparatus  1  includes a heating device  15  downstream in the recording medium conveyance direction of the recording-medium collecting device  30 . In the heating device  15 , a pair of rollers are provided on both sides of the recording-medium conveying device  20 . The heating device  15  heats the recording medium to erasing temperature that is temperature at which a color of a developer on the recording medium is erased. Therefore, the image erasing apparatus  1  subjects the recording medium to image erasing with the heating device  15 . 
     The image erasing apparatus  1  includes a pair of scanners  16 A and  16 B as image reading devices downstream in the recording medium conveyance direction of the heating device  15 . The scanners  16 A and  16 B are provided on both sides of the recording-medium conveying device  20 . The image erasing apparatus  1  determines on the basis of outputs of the scanners  16 A and  16 B whether image erasing for the recording medium is successful. 
     The image erasing apparatus  1  includes, downstream in the recording medium conveyance direction of the scanners  16 A and  16 B, stacking devices  21 A,  21 B, and  21 C configured to store recording media. The image erasing apparatus  1  operates the switching device  22  to thereby stack recording media for which image erasing is unsuccessful in the collection box  31  and stack recording media for which image erasing is successful in the stacking devices  21 A to  21 C while sorting the recording media according to sizes. 
       FIG. 2  is a perspective view of the recording-medium collecting device  30 .  FIG. 3  is a front view of the recording-medium collecting device  30  viewed from a direction of an arrow A in  FIG. 1 . 
     As shown in  FIGS. 2 and 3 , the recording medium collecting device  30  includes a roller lifting and lowering device  32 , driving rollers  31 A 1  and  31 A 2  driven by a driving motor, driven rollers  31 B 1  and  31 B 2  configured to rotate following the driving rollers  31 A 1  and  31 A 2 , and a first brush roller  33 A including a brush  33 . 
     A rotating shaft  33 A 1  of the first brush roller  33 A and a rotating shaft  31 C of the driving rollers  31 A 1  and  31 A 2  are supported by the roller lifting and lowering device  32 . The roller lifting and lowering device  32  is lifted and lowered by a solenoid or the like. 
     The recording-medium collecting device  30  includes a pair of movable plates  34 A and  34 B. The movable plates  34 A and  34 B have plural teeth on sides thereof. The recording-medium collecting device  30  includes motors  36 A and  36 B including gears  35 A and  35 B. The teeth on the sides of the movable plates  34 A and  34 B mesh with the gears  35 A and  35 B. 
     The movable plates  34 A and  34 B rotatably support second brush rollers  33 B 1  and  33 B 2  having the brush  33  and the driven rollers  31 B and  31 B 2 , respectively. 
     The length of the first brush roller  33 A is equal to total length of the second brush rollers  33 B 1  and  33 B 2  and larger than maximum width of a conveyable recording medium. 
     As a material of the brush  33 , plastic such as nylon or animal hair such as pig hair can be used. 
     The first brush roller  33 A and the second brush rollers  33 B 1  and  33 B 2  rotate in a direction opposite to a direction of conveyance of a recording medium and remove tag paper and foreign matters such as bits of eraser grit adhering to the conveyed recording medium from the recording medium. 
       FIG. 4  is a diagram of a state of recording medium collecting operation by the recording-medium collecting device  30 . As shown in  FIG. 4 , when detecting from an output of the double-feed detection sensor  13  or the media sensor  14  that double feed occurs, a recording medium has thickness larger than a first threshold set in advance, or a recording medium has thickness smaller than a second threshold set in advance, the image erasing apparatus  1  causes the recording-medium collecting device  30  to perform the recording medium collecting operation. 
     Specifically, when determining that a recording medium is non-conveyable, the image erasing apparatus  1  lifts the roller lifting and lowering device  32  to pull the brush roller  33 A and the driving rollers  31 A 1  and  31 A 2  upward, i.e., in an arrow X 1  direction and release nip of the recording medium. 
     Subsequently, the image erasing apparatus  1  rotates the motor  36 A to displace the movable plate  34 A in an arrow X 2  direction and rotates the motor  36 B to displace the movable plate  34 B in an arrow X 3  direction. Specifically, the image erasing apparatus  1  opens the movable plates  34 A and  34 B in a vertical direction with respect to the recording medium conveyance direction. 
     According to this recording medium collecting operation, the recording-medium collecting device  30  drops a non-conveyable recording medium in the vertical direction to the collecting box  31  and collects the recording medium. 
     Usually, a jam tends to be caused when a stapled sheet bundle or a sheet is double-fed or a sheet having thickness other than specified thickness is conveyed. In particular, when a conveying path is bent, it is highly likely that a sheet is non-conveyable and jams. However, since the image erasing apparatus  1  conveys a recording medium from the paper feeding device  12  to the recording-medium collecting device  30  without bending the recording medium, it is possible to prevent an unnecessary jam. 
       FIG. 5  is a diagram of recording medium collecting operation by the recording-medium collecting device  30  according to a first application example. As shown in  FIG. 5 , in the recording medium collecting device  30  according to the first application example, the rotating shaft  31 C of the driving rollers  31 A 1  and  31 A 2  is supported by the roller lifting and lowering device  32 . The rotating shaft  33 A 1  of the brush roller  33 A is not supported by the roller lifting and lowering device  32 . 
     Therefore, the driving rollers  31 A 1  and  31 A 2  rise according to the recording medium collecting operation. The brush roller  33 A does not rise according to the recording medium collecting operation. 
       FIG. 6  is a block diagram of the configuration of the image erasing apparatus  1 . As shown in  FIG. 6 , the image erasing apparatus  1  includes a main CPU  501  as a control unit (a controller). The main CPU  501  is connected to a control panel  503  and a ROM and RAM  502  as a storage device. 
     The main CPU  501  is connected to the heating device  15 , the scanners  16 A and  16 B, the media sensor  14 , the double-feed detection sensor  13 , and the roller lifting and lowering device  32 . The main CPU  501  controls the recording-medium conveying device  20 . The main CPU  501  controls ON and OFF and the temperature of the heating device  15 . 
       FIG. 7  is a side view of the configuration of an image erasing apparatus  2  according to a second application example. As shown in  FIG. 7 , the image erasing apparatus  2  includes the paper feeding tray  11  on which recording media to be subjected to image erasing are stacked, the paper feeding device  12  configured to extract a recording medium from the paper feeding tray  11 , the recording-medium conveying device  20  configured to convey the recording medium, and the sensor group including the double-feed detection sensor  13  configured to detect double feed of the recording medium and the media sensor  14  configured to detect the thickness of the recording medium. 
     The recording-medium conveying device  20  includes the plural conveying rollers  20 A and switching devices  22  and  22 A configured to switch a conveying path. 
     The image erasing apparatus  2  includes a collection box  40  downstream in a recording medium conveyance direction of the sensor group. The switching device  22 A is set between the sensor group and the collection box  40 . 
     The recording-medium conveying device  20  is formed on a straight line from the paper feeding device  12  to the collection box  40 . The recording-medium conveying device  20  connecting the paper feeding device  12 , the sensor group, and the collection box  40  is formed on the straight line. The paper feeding device  12 , the sensor group, and the collection box  40  are arranged on the straight line. The image erasing apparatus  2  conveys a recording medium from the paper feeding device  12  to the collection box  40  without bending the recording medium. 
     The image erasing apparatus  2  includes the heating device  15  downstream in the recording medium conveyance direction of the switching device  22 A. In the heating device  15 , a pair of rollers are provided on both sides of the recording-medium conveying device  20 . The heating device  15  heats the recording medium to erasing temperature that is temperature at which a color of a developer on the recording medium is erased. Therefore, the image erasing apparatus  2  subjects the recording medium to image erasing with the heating device  15 . 
     The image erasing apparatus  2  performs the recording medium collecting operation when detecting from an output of the double-feed detection sensor  13  or the media sensor that double feed occurs, a recording medium has thickness larger than a first threshold set in advance, or a recording medium has thickness smaller than a second threshold set in advance. 
     Specifically, when determining that a recording medium is non-conveyable, the image erasing apparatus  2  operates the switching device  22 A and conveys the recording medium in a direction of arrows X 4  and X 5 . The recording medium is collected in the collection box  40 . 
     Usually, a jam tends to be caused when a stapled sheet bundle or a sheet is double-fed or a sheet having thickness other than specified thickness is conveyed. In particular, when a conveying path is bent, it is highly likely that a sheet is non-conveyable and jams. However, since the paper feeding device  12 , the sensor group, and the collection box  40  are arranged on the straight line, it is possible to prevent an unnecessary jam caused when a sheet bundle is caught. 
     When determining that a recording medium is conveyable, the image erasing apparatus  2  operates the switching device  22 A and conveys the recording medium in the direction of the heating device  15 . 
     The image erasing apparatus  2  includes the pair of scanners  16 A and  16 B as image reading devices downstream in the recording medium conveyance direction of the heating device  15 . The scanners  16 A and  16 B are provided on both sides of the recording-medium conveying device  20 . The image erasing apparatus  2  determines on the basis of outputs of the scanners  16 A and  16 B whether image erasing for the recording medium is successful. 
     The image erasing apparatus  2  includes, downstream in the recording medium conveyance direction of the scanners  16 A and  16 B, stacking devices  21 A,  21 B, and  21 D configured to store recording media. The image erasing apparatus  2  operates the switching device  22  to thereby stack recording media for which image erasing is unsuccessful in the stacking device  21 D and stack recording media for which image erasing is successful in the stacking devices  21 A and  21 B while sorting the recording media according to sizes. 
       FIG. 8  is a side view of the configuration of an image erasing apparatus  3  according to a third application example. As shown in  FIG. 8 , the image erasing apparatus  3  includes the paper feeding tray  11  on which recording media to be subjected to image erasing are stacked, a paper-feeding-tray lifting and lowering device  11 A configured to lift and lower the paper feeding tray  11 , the paper feeding device  12  configured to extract a recording medium from the paper feeding tray  11 , the recording-medium conveying device  20  configured to convey the recording medium, and the sensor group including the double-feed detection sensor  13  configured to detect double feed of the recording medium and the media sensor  14  configured to detect the thickness of the recording medium. 
     The recording-medium conveying device  20  includes the plural conveying rollers  20 A and switching devices  22 ,  22 A, and  22 B configured to switch a conveying path. 
     The image erasing apparatus  3  includes the collection box  40  downstream in a recording medium conveyance direction of the sensor group. The switching device  22 A is set between the sensor group and the collection box  40 . 
     The image erasing apparatus  3  includes a discharge box  41  further upstream than the paper feeding tray  11  in the recording medium conveyance direction. 
     The recording-medium conveying device  20  is formed on a straight line from the paper feeding device  12  to the collection box  40  and from the paper feeding device  12  to the discharge box  41 . The recording-medium conveying device  20  connecting the paper feeding device  12 , the sensor group, and the collection box  40  is formed on the straight line. The recording-medium conveying device  20  connecting the paper feeding device  12  and the discharge box  41  is formed on the straight line. 
     The paper feeding device  12 , the sensor group, and the collection box  40  are arranged on the straight line. The paper feeding device  12  and the discharge box  41  are arranged on the straight line. The image erasing apparatus  3  conveys a recording medium from the paper feeding device  12  to the collection box  40  and from the paper feeding device  12  to the discharge box  41  without bending the recording medium. 
     The image erasing apparatus  3  includes the heating device  15  downstream in the recording medium conveyance direction of the switching device  22 A. In the heating device  15 , a pair of rollers are provided on both sides of the recording-medium conveying device  20 . The heating device  15  heats the recording medium to erasing temperature that is temperature at which a color of a developer on the recording medium is erased. Therefore, the image erasing apparatus  3  subjects the recording medium to image erasing with the heating device  15 . 
     The image erasing apparatus  3  performs the recording medium collecting operation when detecting from an output of the double-feed detection sensor  13  or the media sensor that double feed occurs, a recording medium has thickness larger than a first threshold set in advance, or a recording medium has thickness smaller than a second threshold set in advance. 
       FIG. 9  is a side view of recording medium collecting operation by the image erasing apparatus  3  according to the third application example. As shown in  FIG. 9 , when the determining that a recording medium is non-conveyable, first, image erasing apparatus  3  stops conveyance of the recording medium. Subsequently, the image erasing apparatus  3  operates the paper-feeding-tray lifting and lowering device  11 A to lower the paper feeding tray  11 . The image erasing apparatus  3  operates the switching device  22 B to form a recording medium conveying path reaching from the sensor group to the discharge box  41 . 
     The image erasing apparatus  3  reversely rotates the conveying roller  20 A, conveys the recording medium in a direction of an arrow X 8 , and discharges the recording medium to the discharge box  41 . 
     When determining that a recording medium is conveyable but is folded, the image erasing apparatus  3  operates the switching device  22 A to convey the recording medium to the collection box  40  and collect the recording medium. The image erasing apparatus  3  determines, according to whether sheet thickness detected by the media sensor changes, whether the recording medium is folded. 
     When determining that the recording medium is conveyable and is not folded, the image erasing apparatus  3  operates the switching device  22 A to convey the recording medium in a direction of the heating device  15 . 
     The image erasing apparatus  3  includes the pair of scanners  16 A and  16 B as image reading devices downstream in the recording medium conveyance direction of the heating device  15 . The scanners  16 A and  16 B are provided on both sides of the recording-medium conveying device  20 . The image erasing apparatus  3  determines on the basis of outputs of the scanners  16 A and  16 B whether image erasing for the recording medium is successful. 
     The image erasing apparatus  3  includes, downstream in the recording medium conveyance direction of the scanners  16 A and  16 B, the stacking devices  21 A,  21 B,  21 C, and  21 D configured to store recording media. The image erasing apparatus  3  operates the switching device  22  to thereby stack recording media for which image erasing is unsuccessful in the stacking device  21 D and stack recording media for which image erasing is successful in the stacking devices  21 A to  21 C while sorting the recording media according to sizes. 
     As explained above, each of the image erasing apparatuses  1 ,  2 , and  3  according to this embodiment includes the paper feeding tray  11  configured to feed recording medium, the sensor group including the double-feed detection sensor  13  configured to detect double feed of the recording medium and the media sensor  14  configured to detect the thickness of the recording medium, the collecting device configured to drop the recording medium in the vertical direction and collect the recording medium, and the recording-medium conveying device  20  configured to convey the recording medium. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and apparatuses described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are indeed to cover such forms or modifications as would fall within the scope and spirit of the inventions.