Abstract:
An image forming device includes an image forming section, a plurality of recording-medium supply units, a transportation guide forming a plurality of transportation paths, a full-width cleaning member, a plurality of recording-medium separating members, and at least one partial cleaning member provided for each recording-medium separating member. The plurality of transportation paths joins together to provide a single main transportation path reaching the image forming section. The full-width cleaning member is disposed in the single main transportation path. The full-width cleaning member has a full-width cleaning portion wider than a recording medium. Each partial cleaning member has a partial cleaning portion wider than is the corresponding recording-medium separating member.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to an image forming device such as a laser printer.  
         [0003]     2. Description of Related Art  
         [0004]     An image forming device such as a laser printer is usually provided with a paper feed mechanism for feeding paper and an image forming mechanism for forming an image on the fed paper.  
         [0005]     The paper feed mechanism is provided with a paper feed tray in which paper is stacked in a pile, and a paper feed roller and a paper feed pad disposed above one end of the paper feed tray and disposed to confront each other. Paper at the top of the paper feed tray is pinched between the paper feed roller and the paper feed pad by rotation of the paper feed roller, and is fed one sheet at a time.  
         [0006]     The image forming mechanism is provided with a photosensitive drum and, around the photosensitive drum, a charging device, a scanner device, a developing roller, and a transfer roller, in that order following the direction of rotation of the photosensitive drum. As the photosensitive drum rotates, the surface of the photosensitive drum is first uniformly charged by the charging device, then exposed by high-speed laser beam scan from the scanner device, and an electrostatic latent image is formed based on predetermined image data. Next, through rotation of the developing roller, toner held on the developing roller is supplied to the electrostatic latent image formed on the surface of the photosensitive drum and held selectively, whereby a visible image is formed. Then, while paper fed from the paper feed mechanism passes between the photosensitive drum and the transfer roller, the visible image held on the surface of the photosensitive drum is transferred to the paper, thereby forming a predetermined image on the paper.  
         [0007]     In the above-described image forming device, since paper is fed one sheet at a time while being pinched between the paper feed roller and the separation pad, paper dust may be generated on the paper due to friction between the paper feed roller and the separation pad. In addition, foreign matter such as paper dust may be generated over the entirety of the paper when the paper is cut. If such paper dust mixes with the toner in the image forming mechanism, a problem of image quality degradation will occur.  
         [0008]     Accordingly, for example, Japanese patent-application publication No. 2003-81476 discloses a device in which a paper dust removing roller of approximately the same width as the separation pad, and a paper dust removing roller of approximately the same width as the paper, are disposed downstream of the paper feed roller in the paper transportation direction. Thus, paper dust generated on paper can be eliminated in a well-balanced manner before the paper is transported to the image forming mechanism.  
       SUMMARY OF THE INVENTION  
       [0009]     However, in the device disclosed in Japanese patent-application publication No. 2003-81476, the dust removing rollers of approximately the same width as the paper are not provided for all paper feed paths, resulting in a problem of failing to eliminate paper dust generated on paper in a well-balanced manner for all the paper used.  
         [0010]     In view of the above-described drawbacks, it is an objective of the present invention to provide an image forming device that can eliminate foreign matter effectively, and can form high-quality images, for paper transported from any paper feed path in the image forming device.  
         [0011]     In order to attain the above and other objects, the present invention provides an image forming device. An image forming device includes an image forming section, a plurality of recording-medium supply units, a transportation guide, a full-width cleaning member, a plurality of recording-medium separating members, and at least one partial cleaning member provided for each recording-medium separating member. The image forming section forms an image on an image formation surface of a recording medium. The recording medium has a width in a widthwise direction orthogonal to a recording-medium transportation direction. Each of the plurality of recording-medium supply units supplies the image forming section with the recoding medium. The transportation guide forms a plurality of transportation paths. Each transportation path connects a corresponding one of the plurality of recording-medium supply units to the image forming section. The recording medium is transported from each recording-medium supply unit to the image forming section in the recording-medium transportation direction. The plurality of transportation paths joins together to provide a single main transportation path reaching the image forming section. The full-width cleaning member is disposed in the single main transportation path. The full-width cleaning member is contactable with the image formation surface of the recording medium. The full-width cleaning member has a full-width cleaning portion for removing foreign matter adhering to the image formation surface of the recording medium. The full-width cleaning portion has a first width greater than the width of the recording medium in the widthwise direction. Each of the plurality of recording-medium separating members is disposed at a position, in each of the plurality of transportation paths, between a corresponding recording-medium supply unit and the full-width cleaning member. Each recording-medium separating member is contactable with one surface of the recording medium, thereby separating only one sheet of the recording medium to be transported downstream. Each recording-medium separating member has a second width in the widthwise direction smaller than the width of the recording medium. The at least one partial cleaning member is provided for each recording-medium separating member. The at least one partial cleaning member is disposed at a position, in a corresponding transportation path, between a corresponding recording-medium separating member and the image forming section. Each partial cleaning member is contactable with the one surface of the recording medium. Each partial cleaning member has a partial cleaning portion for removing foreign matter adhering to the one surface of the recording medium. The partial cleaning portion has a third width greater than the second width of the corresponding recording-medium separating member. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     The above and other objects, features and advantages of the invention will become more apparent from reading the following description of the preferred embodiments taken in connection with the accompanying drawings in which:  
         [0013]      FIG. 1  is a side cross-sectional view showing principal parts of a laser printer according to an embodiment of the present invention;  
         [0014]      FIG. 2  is an enlarged side cross-sectional view showing paper feed transportation paths of the laser printer shown in  FIG. 1 ;  
         [0015]      FIG. 3 ( a ) is a plan view of paper used in the laser printer shown in  FIG. 1 ;  
         [0016]      FIG. 3 ( b ) is a cross-sectional view of a third paper dust removing roller in the laser printer shown in  FIG. 1 ;  
         [0017]      FIG. 3 ( c ) is a cross-sectional view of a first paper dust removing roller and a second paper dust removing roller in the laser printer shown in  FIG. 1 ;  
         [0018]      FIG. 3 ( d ) is a cross-sectional view of a pad member in the laser printer shown in  FIG. 1 ; and  
         [0019]      FIG. 4  is a side view of a paper dust transportation section of the laser printer shown in  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0020]     An image forming device according to a preferred embodiment of the present invention will be described while referring to the accompanying drawings.  
         [0021]     As shown in  FIG. 1 , a laser printer  1  forms an image by electrophotography, and is provided with, in a main casing  2 , a paper supply cassette  4  for feeding paper  3  as a recording medium, an image forming section  5  for forming predetermined images on the fed paper  3 , and so forth.  
         [0022]     The paper supply cassette  4  is disposed, in the bottom area within the main casing  2 . The paper supply cassette  4  includes a removable paper feed tray  6 , a paper feed mechanism section  7  fitted to one end of the paper feed tray  6 , a paper pressure plate  8  fitted inside the paper feed tray  6 , a first transportation section  9  located downstream in a paper transportation direction with respect to the paper feed mechanism section  7  (hereinafter, “upstream in the paper transportation direction” and “downstream in the paper transportation direction” may be referred to simply as “upstream” and “downstream”), a second transportation section  10  and a third transportation section  11 , and registration rollers  45  located downstream in the paper transportation direction with respect to the first transportation section  9  and the second transportation section  10 .  
         [0023]     The paper feed tray  6  is box-shaped and has a top that can be opened to allow the paper  3  to be accommodated. The paper feed tray  6  can be inserted into and removed from the bottom part of the main casing  2  horizontally.  
         [0024]     As shown in  FIGS. 1 and 2 , the paper feed mechanism section  7  includes a pickup roller  12   a  that picks up the paper  3  on the paper pressure plate  8 , a separation roller  12   b  that has a surface with a higher coefficient of friction than a coefficient of friction of a pad member  13   b  described later, and a separation pad  13  confronting the separation roller  12   b.  The separation pad  13  includes a support frame  13   a,  the pad member  13   b,  and a spring  13   c.    
         [0025]     The pickup roller  12   a  picks up the paper  3  on the paper pressure plate  8 , and feeds the paper  3  to the separation roller  12   b  side in a first transportation path  43 .  
         [0026]     The separation roller  12   b  is positioned in the first transportation path  43  so as to pinch the paper  3  picked up by the pickup roller  12   a  between the separation roller  12   b  and the pad member  13   b,  such that one sheet of the paper  3  is transported downstream in the paper transportation direction.  
         [0027]     As shown in  FIG. 2 , the support frame  13   a  includes a flat plate-shaped member  13   a   1  and a support member  13   a   2 , and is formed as a member with an L-shaped cross section. The flat plate-shaped member  13   a   1  is disposed below the separation roller  12   b  and confronts the separation roller  12   b.  The support member  13   a   2  is connected to one end of the flat plate-shaped member  13   a   1 , and is formed to bend downward approximately at a right-angle from the one end of the flat plate-shaped member  13   a   1 . An upper end portion  13   a   3  of the support member  13   a   2  is pivotally supported to a casing (not shown), such that the separation pad  13  can be pivotally moved. The pad member  13   b  is inset in a concave portion on the side of the flat plate-shaped member  13   a   1  that confronts the separation roller  12   b.  The spring  13   c  is disposed on the other side that is an opposite side to the separation roller  12   b.  The spring  13   c  urges the flat plate-shaped member  13   a   1 , such that the pad member  13   b  is pressed against the separation roller  12   b.    
         [0028]     As shown in  FIG. 3 ( d ), the pad member  13   b  has an approximately rectangular plate shape and is formed from a urethane rubber or similar elastic member. A width B of the pad member  13   b  in the widthwise direction orthogonal to the paper transportation direction (hereinafter “width in the direction orthogonal to the paper transportation direction” may be referred to simply as “width”) is smaller than a width A of the paper  3  shown in  FIG. 3 ( a ). The width A is the maximum width of the paper  3  for which printing can be performed by the laser printer  1 . In other words, the pad member  13   b  has a width that provides contact with only the widthwise center part of the paper  3  for feeding the paper  3 .  
         [0029]     As shown in  FIG. 1 , the paper pressure plate  8  allows the paper  3  to be stacked in a pile. The paper pressure plate  8  is pivotally supported about the farther end from the pickup roller  12   a,  enabling its nearer end to move up and down. The paper pressure plate  8  is raised by a pressure plate raising mechanism (not shown). At this time, topmost paper  3  contacts the pickup roller  12   a  and further raises the pickup roller  12   a,  and stops at a position at which a sensor (not shown) detects the pickup roller  12   a.  The pickup roller  12   a  is forced downward by a spring (not shown) and is pressed against the paper pressure plate  8 . Then the topmost paper  3  is picked up by the rotation of the pickup roller  12   a  and transported to the separation roller  12   b.  By being pinched between the separation roller  12   b  and the pad member  13   b,  the paper  3  is separated and fed one sheet at a time by the cooperative action of the separation roller  12   b  and the pad member  13   b.  The first transportation path  43  is formed by a transportation guide  81  between the paper feed mechanism section  7  and the image forming section  5 . The fed paper  3  is sent to the registration rollers  45  by the first transportation section  9 , the second transportation section  10 , and the third transportation section  11 , along the first transportation path  43 . The registration rollers  45  include a pair of rollers. The registration rollers  45  send the paper  3  to the image forming section  5  after predetermined registration of the paper  3 .  
         [0030]     As shown in  FIG. 1 , the image forming section  5  includes a scanner section  17 , a process section  18 , a fixing section  19 , and so forth.  
         [0031]     The scanner section  17  is disposed in an upper area within the main casing  2 , and includes a laser emitting section (not shown), a polygonal mirror  20 , lenses  21   a  and  21   b,  reflecting mirrors  22   a  through  22   c,  and so forth. In the scanner section  17 , a laser beam based on predetermined image data emitted from the laser emitting section is irradiated through or reflected from the polygonal mirror  20 , the lens  21   a,  the reflecting mirrors  22   a  and  22   b,  the lens  21   b,  and the reflecting mirror  22   c,  in this order, as shown by the single-dot chain line, and is irradiated onto the surface of a photosensitive drum  23  of the process section  18  in a high-speed scan.  
         [0032]     The process section  18  is positioned below the scanner section  17 , and is detachably mounted in the main casing  2 . The process section  18  includes the photosensitive drum  23 , a developing cartridge  24 , a transfer roller  25 , and a scorotron-type charger  30 . The developing cartridge  24  is detachably mounted to the process section  18 , and includes a toner container  26 , a developing roller  27 , a thickness regulating blade  28 , a toner supply roller  29 , and so forth.  
         [0033]     The toner container  26  is filled with positively charged, non-magnetic, single-component polymer toner. The toner is supplied to the developing roller  27  by the toner supply roller  29 , and is held on the developing roller  27  as a thin layer of a certain thickness by the scraping action of the thickness regulating blade  28 . The photosensitive drum  23  is positioned to confront the developing roller  27 , and is rotatable. The drum body of the photosensitive drum  23  is grounded, and is formed of a positively-charged photosensitive layer formed from polycarbonate or the like.  
         [0034]     As the photosensitive drum  23  rotates in the direction indicated by the arrow, the surface of the photosensitive drum  23  is uniformly positively charged by the scorotron-type charger  30 , and is then exposed by a high-speed laser S beam scan by the scanner section  17 , and an electrostatic latent image is formed. Subsequently, when the photosensitive drum  23  is opposed to the developing roller  27 , the positively-charged toner held on the developing roller  27  is supplied to and selectively held by the electrostatic latent image formed on the surface of the photosensitive drum  23 , that is, portions exposed by the laser beam and whose potential has fallen on the surface of the uniformly positively-charged photosensitive drum  23 . In this way, the image becomes visible and transfer developing can be performed.  
         [0035]     The transfer roller  25  is located below and confronts the photosensitive drum  23 . The transfer roller  25  has a roller of conductive rubber material covering a metallic roller shaft, and has a predetermined transfer bias applied with respect to the photosensitive drum  23 . Thus, the visible image held on the photosensitive drum  23  is transferred to the paper  3  while the paper  3  passes between the photosensitive drum  23  and the transfer roller  25 . Then the paper  3  onto which the visible image has been transferred is transported to the fixing section  19 .  
         [0036]     The fixing section  19  is located downstream of the process section  18 . The fixing section  19  includes a heating roller  31 , a pressure roller  32  that applies pressure to the heating roller  31 , and a transport rollers  33  located downstream of the heating roller  31  and the pressure roller  32 .  
         [0037]     The heating roller  31  is metallic and is provided with a halogen lamp for heating. While the paper  3  passes between the heating roller  31  and the pressure roller  32 , the heating roller  31  heat-fixes the toner transferred onto the paper  3  in the process section  18 . Then the paper  3  is transported to the paper discharge rollers  35  by the transport rollers  33  of the fixing section  19 . After being transported to the paper discharge rollers  35 , the paper  3  is discharged onto a discharge tray  36 .  
         [0038]     A paper sensor  82  is disposed between the heating roller  31  and the transport rollers  33 . At the time of reverse transportation of the paper  3  described later, when the rear end of the paper  3  is detected by the paper sensor  82 , the paper discharge rollers  35  are switched from forward rotation to reverse rotation at predetermined timing after the detection timing.  
         [0039]     With the laser printer  1 , the developing roller  27  recovers residual toner remaining on the surface of the photosensitive drum  23  after the transfer roller  25  has performed transfer. That is, the residual toner is recovered by a so-called cleanerless developing method since the residual toner is recovered by the cleanerless developing method, there is no need for a special member such as a blade for storing removing residual toner, or for a storage section for waste toner, thereby simplifying the device configuration.  
         [0040]     The laser printer  1  is provided with the reverse mechanism  37  that reverses the paper  3 , and a retransportation tray  40  that retransports the paper  3  to the image forming section  5  in order to form images on both sides of the paper  3 . The reverse mechanism  37  includes the paper discharge rollers  35 , a flapper  38 , and a reverse guide  39 . The reverse mechanism  37  and the retransportation tray  40  may be integrated and detachably mounted to the main casing  2  as a unit.  
         [0041]     The paper discharge rollers  35  include a pair of rollers, and enable switching between forward and reverse rotation. As described above, when the paper  3  is to be discharged onto the discharge tray  36 , the paper discharge rollers  35  rotate in the forward direction and transport the paper  3  in the paper transportation direction. However, when the paper  3  is to be reversed and transported in the reverse direction, the paper discharge rollers  35  rotate in the reverse direction.  
         [0042]     The reverse guide  39  forms a reverse transportation path  41  in a vertical direction together with the flapper  38  so that the paper  3  can be transported from the paper discharge rollers  35  to the retransportation tray  40  located below the image forming section  5 . The upstream end of the reverse transportation path  41  is located near the paper discharge rollers  35  and the downstream end thereof is located near the retransportation tray  40 . In the reverse transportation path, the paper  3  is transported with its widthwise center as a reference (instead of transporting the paper  3  with its widthwise end as a reference), which is so-called center registration feed.  
         [0043]     The flapper  38  is provided near a junction position M 3  that is a junction of a paper discharge path  42  and the reverse transportation path  41 . The flapper  38  can be pivotally moved. More specifically, the flapper  38  can switch the transportation direction of the paper  3  reversed by the paper discharge rollers  35 , from the direction toward the paper discharge rollers  35  to the direction toward the retransportation tray  40  in accordance with excitation or non-excitation of a solenoid (not shown).  
         [0044]     The retransportation tray  40  is approximately plate-shaped, and is disposed approximately horizontally above the paper feed tray  6 . The upstream end of the retransportation tray  40  is located near the rear end of the reverse transportation path  41 , and the downstream end is located below the registration rollers  45 .  
         [0045]     The reverse mechanism  37  is operated as described below. When the paper  3  with an image formed on one side is fed from the paper discharge path  42  to the paper discharge rollers  35  by the transport rollers  33 , the paper discharge rollers  35  rotate forward while pinching the paper  3  and transport the paper  3  initially toward the outside (the discharge tray  36  side). Subsequently, when a greater part of the paper  3  has been fed toward the outside and the rear end of the paper  3  is between the paper discharge rollers  35 , forward rotation is halted. Next, the paper discharge rollers  35  rotate in the reverse direction, and the flapper  38  switches the transportation direction so that the paper  3  is transported to the reverse transportation path  41 . Thus, the paper  3  is transported to the reverse transportation path  41  with its lengthwise direction reversed. The timing for switchover of the paper discharge rollers  35  from forward to reverse rotation is controlled so as to be a predetermined time after the rear end of the paper  3  is detected by the paper sensor  82 , as described above. When transportation of the paper  3  ends, the flapper  38  is switched to its original state, that is, the state in which the paper  3  fed from the transport rollers  33  is fed to the paper discharge rollers  35 . Next, the paper  3  transported in the reverse direction to the reverse transportation path  41  is further transported to the retransportation tray  40 . Then, the paper  3  is transported upward from the retransportation tray  40 , and transported to the registration rollers  45 . The paper  3  transported to the registration rollers  45  has predetermined registration applied again in the reversed state, and is then sent toward the image forming section  5 , by which a predetermined image is formed on the reverse side of the paper  3 .  
         [0046]     The retransportation tray  40  includes a tray body  50  and oblique rollers  51 . The tray body  50  has an approximately rectangular plate shape, and is disposed approximately horizontally above the paper feed tray  6 . The upstream end of the tray body  50  is connected to the reverse guide  39 . The downstream end of the tray body  50  is connected to a retransportation path  53  that is connected to the first transportation path  43 , in order to guide the paper  3  from the tray body  50  to the second transportation section  10 .  
         [0047]     The three oblique rollers  51  are provided in the tray body  50  at predetermined intervals along the paper transportation direction for transporting the paper  3 . The paper  3  is transported while in contact with a reference plate (not shown).  
         [0048]     Each oblique roller  51  is provided with an oblique drive roller  54  and an oblique follow roller  55 . The oblique drive roller  54  is located near the reference plate (not shown) disposed at one widthwise end of the tray body  50 . The axes of the oblique drive rollers  54  are positioned  5  in a direction approximately orthogonal to the paper transportation direction. The oblique follow roller  55  confronts the oblique drive roller  54  and sandwiches the paper  3  with the oblique drive roller  54 . The axes of the oblique follow rollers  55  are positioned such that the paper  3  is transported in a direction oblique with regard to the paper transport direction toward the reference plate.  
         [0049]     The paper  3  sent from the reverse transportation path  41  to the tray body  50  is transported by the oblique rollers  51  via the retransportation path  53  while one widthwise edge of the paper  3  is in contact with the reference plate, and toward the image forming section  5 , with the front and back reversed. When the paper  3  is transported to the image forming section  5 , the rear surface thereof is brought into contact with the photosensitive drum  23 , the visible image is transferred and then fixed by the fixing section  19 , and the paper  3  is discharged to the discharge tray  36  with images formed on both sides.  
         [0050]     As shown in  FIG. 2 , the laser printer  1  is provided with the first transportation section  9 , the second transportation section  10 , and the third transportation section  11 , all positioned in the first transportation path  43 . With this construction, the laser printer  1  can remove, in a well-balanced manner, paper dust originally generated on the entire paper  3  when the paper  3  is cut and paper dust generated on the surface of the paper  3  due to friction between the pad member  13   b  and the separation roller  12   b  of the paper feed mechanism section  7 . Also, as shown in  FIG. 4 , a paper dust transportation section  60  is provided to transport paper dust removed by the third transportation section  11  to a storage tank  71  described later.  
         [0051]     The relationships among the transportation paths  43 ,  44 ,  46 , and  53  are described. The first transportation path  43 , the second transportation path  44 , the transportation path  46 , and the retransportation path  53  are formed by the transportation guide  81 . The first transportation path  43  is formed to pass through the paper feed mechanism section  7 , the first transportation section  9 , the second transportation section  10 , and the third transportation section  11 . The second transportation path  44  is formed to pass through the multipurpose paper feed mechanism section  15 , the second transportation section  10 , and the third transportation section  11 . The retransportation path  53  joins or merges with the first transportation path  43  at a junction position M 1 . The first transportation path  43  and the second transportation path  44  joins with each other at a junction position M 2 . Thus, the first transportation path  43  and the second transportation path  44  overlaps in a section downstream of the junction position M 2 . The transportation path  46  is formed in the overlapped section between the junction position M 2  and the registration rollers  45 . In other words, the transportation path  46  is a part of the first transportation path  43  and the second transportation path  44 .  
         [0052]     The first transportation section  9  is positioned downstream in the paper transportation direction with respect to the separation roller  12   b  of the paper feed mechanism section  7  at the forward portion of the first transportation path  43 . The first transportation section  9  is positioned at a predetermined distance from the separation roller  12   b  and further upstream than the junction position M 1  in the first transportation path  43 . The first transportation section  9  includes a first transportation roller  9   a  that transports the paper  3 , a first paper dust removing roller  9   b  confronting the same surface of the paper  3  as the surface confronting the separation pad  13 , and a first sponge member  9   c  positioned below the first paper dust removing roller  9   b.    
         [0053]     The first transportation roller  9   a  confronts the first transportation path  43  from the inner side. The first transportation roller  9   a  has a metallic roller shaft  9   d  covered with a rubber roller  9   e,  and is rotatable in the direction indicated by the arrow (clockwise direction in  FIG. 2 ) by the power transmitted from a motor (not shown).  
         [0054]     The first paper dust removing roller  9   b  confronts the first transportation path  43  from the outer side. The first paper dust removing roller  9   b  has a metallic roller shaft  9   f  covered with a resin roller  9   g  whose surface is easily charged. The resin roller  9   g  is, for example, a roller of fluororesin or a roller with a fluororesin coated surface. As shown in  FIG. 3 ( c ), the first paper dust removing roller  9   b  is positioned in an approximately center position with respect to the first transportation roller  9   a,  such that the first paper dust removing roller  9   b  overlaps the separation pad  13  in the paper transportation direction. Accordingly, the first paper dust removing roller  9   b  can contact the surface of the paper  3  that has contacted the pad member  13   b  (the image formation surface). More specifically, the first paper dust removing roller  9   b  can contact a part that has contacted the pad member  13   b  (the approximately center part). The width of the roller  9   g  of the first paper dust removing roller  9   b  is identical to the width of a roller  10   g  of a second paper dust removing roller  10   b  described later, but smaller than the width of a roller  11   g  of a third paper dust removing roller  11   b  described later, and slightly greater than the width B of the pad member  13   b.    
         [0055]     The first paper dust removing roller  9   b  is driven by the first transportation roller  9   a.  The first paper dust removing roller  9   b  is rotatable in the direction indicated by the arrow, that is, the same direction as the paper transportation direction in the part confronting the first transportation path  43  (counterclockwise direction in  FIGS. 1 and 2 ). The first paper dust removing roller  9   b  transports the paper  3  pinched between the first transportation roller  9   a  and the first paper dust removing roller  9   b  while removing paper dust from the paper  3 .  
         [0056]     As shown in  FIG. 2 , the first sponge member  9   c  is composed of a material such as urethane foam that easily charges the first paper dust removing roller  9   b.  The first sponge member  9   c  is positioned beneath the first paper dust removing roller  9   b  and is pressed against the first paper dust removing roller  9   b,  so as to be able to scrape off paper dust at a scraping position  9   c   1 . The scraping position  9   c   1  contacts a portion of the first paper dust removing roller  9   b  that is a position at a lower side and an opposite side (farther side) from the first transportation path  43 . Thus, the first sponge member  9   c  can scrape off paper dust adhering to the first paper dust removing roller  9   b.  The first sponge member  9   c  also performs frictional charging of the surface of the roller  9   g  of the first paper dust removing roller  9   b  by rubbing against the first paper dust removing roller  9   b.  As shown in  FIG. 3 ( c ), the width of the first sponge member  9   c  is slightly greater than the width of the roller  9   g  of the first paper dust removing roller  9   b.    
         [0057]     The second transportation section  10  is disposed downstream in the paper transportation direction with respect to the first transportation section  9  above the first transportation section  9 . The second transportation section  10  is located downstream of the junction position M 1  of the first transportation path  43  and the downstream end of the retransportation path  53 . Further, the second transportation section  10  is located slightly downstream of the junction position M 2  of the first transportation path  43  and the second transportation path  44 . The second transportation section  10  includes a second transportation roller  10   a  that transports the paper  3 , the second paper dust removing roller  10   b  located so as to confront the same surface as the surface confronting a multipurpose separation pad  15   b  described later, and a second sponge member  10   c  below the second paper dust removing roller  10   b.    
         [0058]     The second transportation roller  10   a  confronts the transportation path  46  from the outer side. The second transportation roller  10   a  has a metallic roller shaft  10   d  covered with a rubber roller be. The second transportation roller  10   a  is rotatable in the direction indicated by the arrow (counterclockwise direction in  FIGS. 1 and 2 ) by the power transmitted from a motor (not shown).  
         [0059]     The second paper dust removing roller  10   b  confronts the transportation path  46  from the inner side. The second paper dust removing roller  10   b  has a metallic roller shaft  10   f  covered with the resin roller  10   g  whose surface is easily charged, such as a roller of fluororesin or a roller with a fluororesin coated surface. As shown in  FIG. 3 ( c ), the second paper dust removing roller  10   b  is positioned in an approximately center position with respect to the second transportation roller  10   a,  such that the second paper dust removing roller  10   b  overlaps the pickup roller  12   a  and the separation roller  12   b  in the paper transportation direction. Accordingly, the second paper dust removing roller  10   b  can contact the surface of the paper  3  that has contacted the pickup roller  12   a  and the separation roller  12   b  (the surface opposite to the image formation surface). More specifically, the second paper dust removing roller  10   b  can contact a part that has contacted the pickup roller  12   a  and the separation roller  12   b  (the approximately center part). As described above, the width of the roller  10   g  of the second paper dust removing roller  10   b  is identical to the width of the roller  9   g  of the first paper dust removing roller  9   b,  but smaller than the width of the roller  11   g  of the third paper dust removing roller  11   b  described later, and slightly greater than the width of the pickup roller  12   a  and the separation roller  12   b.    
         [0060]     The second paper dust removing roller  10   b  is driven by the second transportation roller  10   a.  The second paper dust removing roller  10   b  is rotatable in the direction indicated by the arrow, that is, the same direction as the paper transportation direction in the part confronting the transportation path  46  (clockwise direction in  FIGS. 1 and 2 ). The second paper dust removing roller  10   b  transports the paper  3  pinched between the second transportation roller  10   a  and the second paper dust removing roller  10   b  while removing paper dust from the paper  3 .  
         [0061]     The second sponge member  10   c  is made of a material that easily charges the second paper dust removing roller  10   b,  such as urethane foam. As shown in  FIG. 2 , the second sponge member  10   c  is positioned beneath the second paper dust removing roller  10   b.  The second sponge member  10   c  is pressed against the second paper dust removing roller  10   b,  so as to be able to scrape off paper dust on a lower side of the second paper dust removing roller  10   b  that is opposite from the transportation path  46 . Thus, the second sponge member  10   c  can scrape off paper dust adhering to the second paper dust removing roller  10   b.  The second sponge member  10   c  also performs frictional charging of the surface of the roller  10   g  of the second paper dust removing roller  10   b  by rubbing against the second paper dust removing roller  10   b.  As shown in  FIG. 3 ( c ), the width of the second sponge member  10   c  is slightly greater than the width of the roller  10   g  of the second paper dust removing roller  10   b.    
         [0062]     As shown in  FIG. 2 , the third transportation section  11  is disposed downstream of the second transportation section  10  in the transportation path  46 . The third transportation section  11  is located in the vicinity of the second transportation section  10 . The third transportation section  11  includes a third transportation roller  11   a  that transports the paper  3 , the third paper dust removing roller  11   b  disposed to sandwich the transportation path  46  and to confront the third transportation roller  11   a,  and a third sponge member  11   c  above the third paper dust removing roller  11   b.    
         [0063]     The third transportation roller  11   a  confronts the transportation path  46  from the inner side. The third transportation roller  11   a  has a metallic roller shaft  11   d  covered with a rubber roller  11   e.  The third transportation roller  11   a  is rotatable in the direction indicated by the arrow (clockwise direction in  FIGS. 1 and 2 ) by the power transmitted from a motor (not shown).  
         [0064]     The third paper dust removing roller  11   b  confronts the transportation path  46  from the outer side. The third paper dust removing roller  11   b  has a metallic roller shaft  11   f  covered with the resin roller  11   g  whose surface is easily charged, such as a roller of fluororesin or a roller with a fluororesin coated surface. As shown in  FIG. 3 ( b ), with the third paper dust removing roller  11   b,  the width of the roller  11   g  is slightly greater than the width A of the paper  3 , so as to be contactable with the entire surface of the paper  3 . In addition, the third paper dust removing roller  11   b  contacts the entirety of the surface that has contacted the pad member  13   b  (the image formation surface that will contact the photosensitive drum  23 ).  
         [0065]     As shown in  FIG. 2 , the third paper dust removing roller  11   b  is rotatable in the direction indicated by the arrow, that is, the same direction as the paper transportation direction in the part confronting the transportation path  46  (counterclockwise direction in  FIGS. 1 and 2 ). The third paper dust removing roller  11   b  transports the paper  3  pinched between the third transportation roller  11   a  and the third paper dust removing roller  11   b  while removing paper dust from the paper  3 .  
         [0066]     The third sponge member  11   c  is composed of a material that easily charges the third paper dust removing roller  11   b,  such as urethane foam. The third sponge member  11   c  is positioned above the third paper dust removing roller  11   b.  The third sponge member  11   c  is pressed against the third paper dust removing roller  11   b,  so as to scrape off paper dust at an upper side of the third paper dust removing roller  11   b,  which is an opposite side from the transportation path  46 . Thus, the third sponge member  11   c  can scrape off paper dust adhering to the third paper dust removing roller  11   b.  The third sponge member  11   c  also performs frictional charging of the surface of the roller  11   g  of the third paper dust removing roller  11   b  by rubbing against the third paper dust removing roller  11   b.  As shown in  FIG. 3 ( b ), the width of the third sponge member  11   c  is slightly greater than the width of the third paper dust removing roller  11   b.    
         [0067]     As shown in  FIGS. 2 and 4 , the paper dust transportation section  60  includes a receiving surface  61  and an auger member  62 . The receiving surface  61  receives paper dust scraped by the third sponge member  11   c.  The auger member  62  has an approximately cylindrical shape and transports the paper dust to the storage tank  71 . The paper dust transportation section  60  is constituted as a unit that can be inserted into and removed from the laser printer  1 .  
         [0068]     The receiving surface  61  is formed into a curved concave shape for receiving the auger member  62 . The receiving surface  61  is slightly wider than the width of the third paper dust removing roller  11   b.    
         [0069]     As shown in  FIG. 4 , the auger member  62  includes a shaft  63 , and a first spiral member  64  and a second spiral member  65  both formed in a spiral shape around the shaft  63 .  
         [0070]     The first spiral member  64  is formed along the axial direction on an approximately half portion of the shaft  63 . The first spiral member  64  transports paper dust in one s direction (the direction indicated by arrow X) along the axial direction of the third paper dust removing roller  11   b  through rotation of the shaft  63 . The second spiral member  65  is formed along the axial direction on the other approximately half portion of the shaft  63  on the side opposite to the side on which the first spiral member  64  is formed. The second spiral member  65  transports paper dust in the other direction. (the direction indicated by arrow Y) along the axial direction of the third paper dust removing roller  11   b  through rotation of the shaft  63 .  
         [0071]     With the above-described construction, paper dust received on the receiving surface  61  is transported to both ends of the axial direction (in the directions of the arrow X and the arrow Y) by the first spiral member  64  and the second spiral member  65 . The paper dust is dropped into and accumulated in the storage tank  71  located below the third transportation section  11 .  
         [0072]     As shown in  FIG. 1 , in the laser printer  1 , the reverse transportation path  41 , the retransportation path  53 , the first transportation path  43 , and the paper output path  42  jointly form a closed path for supplying the image forming section  5  with the paper  3  that has passed through the image forming section  5  with front and back sides thereof reversed. In other words, the reverse transportation path  41  forms a part of the closed path. The storage tank  71  is located within the closed path. An opening of the storage tank  71  is located below both the second paper dust removing roller  10   b  and the third paper dust removing roller  11   b.  Accordingly, the storage tank  71  can receive both paper dust removed by the second transportation section  10  and paper dust removed by the third transportation section  11 .  
         [0073]     In the laser printer  1 , the paper  3  stacked in a pile in the paper feed tray  6  is separated and fed one sheet at a time by the cooperative action of the separation roller  12   b  and the separation pad  13 . At the time of the paper feeding, a large amount of paper dust is generated on the image formation surface due to friction with the separation pad  13 . However, when the paper  3  is first transported to the first transportation section  9 , and is pinched between the first transportation roller  9   a  and the first paper dust removing roller  9   b,  the image formation surface comes into contact with the roller  9   g  of the first paper dust removing roller  9   b.  The first paper dust removing roller  9   b  is slightly wider than the width of the separation pad  13 . Thus, paper dust generated on the paper  3  due to friction with the separation pad  13  is scraped off and electrostatically adsorbed by the roller  9   g  of the first paper dust removing roller  9   b,  because the paper dust generated on the paper  3  has a width approximately equal to the width of the pad s member  13   b  and because the width of the resin roller  9   g  is greater than the width B of the pad member  13   b.  Then, when the paper dust adhering to the roller  9   g  of the first paper dust removing roller  9   b  next confronts the first sponge member  9   c  through the rotation of the first paper dust removing roller  9   b,  the paper dust is scraped off by the first sponge member  9   c,  and falls into and is accumulated in a storage tank  72 .  
         [0074]     A large amount of paper dust is also generated on the opposite surface that is opposite to the image formation surface due to friction with the pickup roller  12   a  and the separation roller  12   b  during the paper feeding. However, when the paper  3  is transported to the second transportation section  10 , and pinched between the second transportation roller  10   a  and the second paper dust removing roller  10   b,  the opposite surface comes into contact with the roller  10   g  of the second paper dust removing roller  10   b.  The second paper dust removing roller  10   b  is slightly wider than the width of the pickup roller  12   a  and the separation roller  12   b.  Thus, paper dust generated on the paper  3  due to friction with the pickup roller  12   a  and the separation roller  12   b  is scraped off and electrostatically adsorbed by the roller  10   g  of the second paper dust removing roller  10   b,  because the paper dust generated on the paper  3  has a width approximately equal to the width of the pickup roller  12   a  and the separation roller  12   b  and because the width of the roller  10   g  is greater than the width of the pickup roller  12   a  and the separation roller  12   b.  Then, when the paper dust adhering to the roller  10   g  of the second paper dust removing roller  10   b  next confronts the second sponge member  10   c  through the rotation of the second paper dust removing roller  10   b,  the paper dust is scraped off by the second sponge member  10   c,  and falls into and is accumulated in the storage tank  71 .  
         [0075]     Then, when the paper  3  is transported to the third transportation section  11 , and pinched between the third transportation roller  11   a  and the third paper dust removing roller  11   b,  the image formation surface comes into contact with the roller  11   g  of the third paper dust removing roller  11   b.  At this time, since the third paper dust removing roller  11   b  is slightly wider than the width of the paper  3 , paper dust originally generated on the entirety of the paper  3  during cutting of the paper  3  and so forth, and paper dust remaining after removal by the first paper dust removing roller  9   b,  is scraped off and electrostatically adsorbed by the roller  11   g  of the third paper dust removing roller  11   b.  Then, when the paper dust adhering to the roller  11   g  of the third paper dust removing roller  11   b  next confronts the third sponge member  11   c  through the rotation of the third paper dust removing roller  11   b,  the paper dust is scraped off by the third sponge member  11   c.  The scraped-off paper dust is received by the receiving surface  61 , and then, through the rotation of the auger member  62 , is transported to through-holes  66  at both ends of the axial direction (in the directions of the arrow X and the arrow Y), and is dropped into and accumulated in the storage tank  71  located below the third transportation section  11 .  
         [0076]     Thus, in the laser printer  1 , before the paper  3  fed by the paper feed mechanism section  7  reaches the image forming section  5 , part of paper dust corresponding to the width B of the pad member  13   b  is removed by the first paper dust removing roller  9   b,  part of paper dust corresponding to the width of the pickup roller  12   a  and the separation roller  12   b  is removed by the second paper dust removing roller  10   b,  and part of the paper dust corresponding to the width A of the paper  3  is removed by the third paper dust removing roller  11   b.    
         [0077]     Accordingly, a greater amount of paper dust generated by friction with the pad member  13   b  is removed by the first paper dust removing roller  9   b  and the third paper dust removing roller  11   b,  and a smaller amount of paper dust originally generated on the entirety of the paper  3  during cutting of the paper  3  and so forth is removed by the third paper dust removing roller  11   b.  Also, paper dust generated by friction between the pickup roller  12   a  and the separation roller  12   b  is removed by the second paper dust removing roller  10   b.  As a result, the first transportation section  9 , the second transportation section  10 , and the third transportation section  11  can remove paper dust generated on the image formation surface due to friction with the pad member  13   b  and paper dust originally generated, in a well-balanced manner, and can achieve uniform paper dust removal with little unevenness of removal. Moreover, the first transportation section  9 , the second transportation section  10 , and the third transportation section  11  also can remove paper dust generated due to friction between the pickup roller  12   a  and the separation roller  12   b  on the opposite surface to the image formation surface, and can prevent dispersion of paper dust inside the laser printer  1 . Thus, the laser printer  1  can prevent contamination of the image forming section  5  due to paper dust effectively, and can form high-quality images.  
         [0078]     As the third paper dust removing roller  11   b  is located downstream of the first paper dust removing roller  9   b  in the paper transportation direction, a greater amount of paper dust produced by friction with the pad member  13   b  is first removed by the first paper dust removing roller  9   b,  after which a smaller amount of paper dust originally produced over the entire paper  3  during cutting of the paper  3  and so forth is additionally removed by the third paper dust removing roller  11   b.  Thus, the laser printer  1  can achieve efficient paper dust removal based on differences in the amount of paper dust, enabling more uniform paper dust removal.  
         [0079]     The third paper dust removing roller  11   b  has a width greater than the width of the paper  3 , while the first paper dust removing roller  9   b  has a width greater than the width of the separation pad.  13  and less than the width of the third paper dust removing roller  11   b.  Therefore, the first paper dust removing roller  9   b  is not wider than necessary, allowing costs to be reduced while enabling paper dust to be removed in a well-balanced manner.  
         [0080]     As described above, in the laser printer  1 , the first paper dust removing roller  9   b  is located at a predetermined distance from the separation roller  12   b,  and is located downstream in the paper transportation direction, so as not to come into contact with the separation roller  12   b.    
         [0081]     If the first paper dust removing roller  9   b  is in contact with the separation roller  12   b,  for example, then the paper  3  to be fed next is pulled out slightly following the paper  3  fed before, due to friction between the separation roller  12   b  and the paper  3  fed before. In this case, if a front-end portion of the paper  3  was held between the separation roller  12   b  and the first paper dust removing roller  9   b,  and the laser printer  1  was stopped in that state, the front-end portion of the paper  3  pinched between the separation roller  12   b  and the first paper dust removing roller  9   b  might tend to curl. In such a case, when the paper  3  was next supplied, a paper jam may occur or an imperfect image may be produced on the curled front-end portion.  
         [0082]     However, because the first paper dust removing roller  9   b  is located so as not to come into contact with the separation roller  12   b,  even if the paper  3  to be fed next should be pulled out slightly following the previously fed paper  3 , the paper  3  will not be held between the separation roller  12   b  and the first paper dust removing roller  9   b.  Thus, curling of the front-end portion of the paper  3  can be prevented. Accordingly, the laser printer  1  can achieve satisfactory paper feeding at all times while also performing good paper dust removal.  
         [0083]     In the first transportation section  9 , the second transportation section  10 , and the third transportation section  11 , because the first sponge member  9   c  for scraping off paper dust adhering to the first paper dust removing roller  9   b  is provided to confront the first paper dust removing roller  9   b,  the second sponge member  10   c  for scraping off paper dust adhering to the second paper dust removing roller  10   b  is provided to confront the second paper dust removing roller  10   b,  and the third sponge member  11   c  for scraping off paper dust adhering to the third paper dust removing roller  11   b  is provided to confront the third paper dust removing roller  11   b,  paper dust adhering to the first paper dust removing roller  9   b,  the second paper dust removing roller  10   b,  and the third paper dust removing  10  roller  11   b  are scraped off by the first sponge member  9   c,  the second sponge member  10   c,  and the third sponge member  11   c,  respectively. Thus, the paper dust removal capability of the first paper dust removing roller  9   b,  the second paper dust removing roller  10   b,  and the third paper dust removing roller  11   b  can be maintained, and good paper dust removal over a long period can be achieved.  
         [0084]     As described above, the widths of the first sponge member  9   c,  the second sponge member  10   c,  and the third sponge member  11   c  are formed so as to be slightly greater than the widths of the first paper dust removing roller  9   b,  the second paper dust removing roller  10   b,  and the third paper dust removing roller  11   b,  respectively. Accordingly, paper dust can be scraped satisfactorily even if paper dust on the paper  3  spreads slightly in the width direction due to contact with the first paper dust removing roller  9   b,  the second paper dust removing roller  10   b,  and the third paper dust removing roller  11   b.    
         [0085]     In the laser printer  1 , the paper  3  fed by the paper feed mechanism section  7  is first pinched between the first paper dust removing roller  9   b  and the first transportation roller  9   a  and transported while paper dust is removed, then pinched between the second paper dust removing roller  10   b  and the second transportation roller  10   a  and transported while paper dust is removed, and then further pinched between the third paper dust removing roller  11   b  and the third transportation roller  11   a  and transported while paper dust is removed. The paper  3  can be transported smoothly to the image forming section  5  while paper dust can be removed in a well-balanced manner.  
         [0086]     The third paper dust removing roller  11   b  is not driven by the third transportation roller  11   a,  but instead motive power is input to the third paper dust removing roller  11   b  from a separate motor (not shown) via an input gear  11   h,  enabling the third paper dust removing roller  11   b  to be driven by itself. Thus, even if torque load due to contact with the paper  3  and the third sponge member  11   c  is applied to the entirety of the roller  11   g  of the third paper dust removing roller  11   b,  the third paper dust removing roller  11   b  can be rotated smoothly by its own drive force, and good paper dust removal and transportation can be achieved.  
         [0087]     The laser printer  1  is provided with the reverse mechanism  37 , and the first transportation section  9  is located upstream of the junction position M 1  of the retransportation path  53  and the first transportation path  43 , while the second transportation section  10  is located downstream of the junction position M 1 , and the third transportation section  11  is located downstream of the second transportation section  10 .  
         [0088]     With the above-described construction, since the first paper dust removing roller  9   b  is located upstream of the junction position M 1 , the first paper dust removing roller  9   b  comes into contact with only the paper  3  fed from the paper feed mechanism section  7 . On the other hand, since the second paper dust removing roller  10   b  and the third paper dust removing roller  11   b  are located downstream of the junction position M 1 , the second paper dust removing roller  10   b  and the third paper dust removing roller  11   b  come into contact with both the paper  3  fed from the paper feed mechanism section  7  and the paper  3  retransported from the retransportation path  53 .  
         [0089]     Thus, the first paper dust removing roller  9   b  removes only a greater amount of paper dust generated on paper fed from the paper feed mechanism section  7  by friction with the pad member  13   b,  while the second paper dust removing roller  10   b  removes paper dust generated by friction between the pickup roller  12   a  and the separation roller  12   b  and paper dust on the paper  3  retransported from the retransportation path  53 . In addition, the third paper dust removing roller  11   b  removes paper dust on the paper  3  fed from the paper feed mechanism section  7  from which the majority of a greater amount of paper dust generated by friction with the pad member  13   b  has already been removed by the first paper dust removing roller  9   b.  The third paper dust removing roller  11   b  also removes paper dust of the paper  3  retransported from the retransportation path  53 . Thus, paper dust can be removed effectively according to the amount of paper dust adhering to the paper  3 .  
         [0090]     The laser printer  1  in the present embodiment is provided with a single first transportation section  9 , a single second transportation section  10 , and a single third transportation section  11 . However, a plurality of each of the first transportation section  9 , the second transportation section  10 , and the third transportation section  11  may be provided. Alternatively, a plurality of any one of the first transportation section  9 , the second transportation section  10 , or the third transportation section  11  may be provided.  
         [0091]     The first transportation section  9  provided with the first paper dust removing roller  9   b,  the second transportation section  10  provided with the second paper dust removing roller  10   b,  and the third transportation section  11  provided with the third paper dust removing roller  11   b  are located in this order in the paper transportation downstream direction, but the order of the transportation sections  9 ,  10 , and  11  may be changed. For example, the second transportation section  10 , the third transportation section  11 , and the first transportation section  9  may be disposed in this order in the paper transportation downstream direction.  
         [0092]     In this case, because paper dust on the paper  3  spreads slightly in the paper width direction due to contact with the third paper dust removing roller  11   b,  it is desirable that the widths of the first paper dust removing roller  9   b  and the first sponge member  9   c  be greater than the widths in the above-described embodiemnt.  
         [0093]     The locations of drive rollers and driven (follow) rollers of the first transportation section  9 , the second transportation section  10 , and the third transportation section  11  may also be reversed in terms of which is on the inner side and which is on the outer side of the closed path as compared with the above-described embodiment.  
         [0094]     As shown in  FIG. 1 , the laser printer  1  is provided with a multipurpose tray  14  on which the paper  3  of an arbitrary size is stacked, and a multipurpose paper feed mechanism section  15  for feeding the paper  3  stacked in the multipurpose tray  14 .  
         [0095]     As shown in  FIG. 2 , the multipurpose paper feed mechanism section  15  includes a multipurpose paper feed roller  15   a  and the multipurpose separation pad  15   b  opposing the multipurpose paper feed roller  15   a.  The multipurpose paper feed mechanism section  15  is disposed at a position along the second transportation path  44 . The multipurpose paper feed mechanism section  15  picks up the paper  3  by the multipurpose paper feed roller  15   a,  and separates the paper  3  by contacting the paper  3 , so that one sheet of the paper  3  is transported downstream in the second transportation path  44 .  
         [0096]     The multipurpose separation pad  15   b  includes a supporting frame  15   c,  a multipurpose pad member  15   d,  and a spring  15   e.    
         [0097]     The supporting frame  15   c  has a one end portion  15   c   1  and an other end portion  15   c   2 , both of which are formed integrally. The one end portion  15   c   1  is flat plate-shaped. The one end portion  15   c   1  is disposed below the multipurpose paper feed roller  15   a  and confronts the multipurpose paper feed roller  15   a.  The other end portion  15   c   2  has an L-shaped cross section, and is pivotally supported to the main casing  2  by a support shaft  15   c   3 , such that the supporting frame  15   c  can be pivotally moved about the support shaft  15   c   3 . The multipurpose pad member  15   d  is inset in a concave portion on a side of the one end portion  15   c   1  that confronts the multipurpose paper feed roller  15   a.  The spring  15   e  is disposed on the other side. The spring  15   e  urges the one end portion  15   c   1  such that the multipurpose pad member  15   d  is pressed against the multipurpose paper feed roller  15   a.    
         [0098]     The multipurpose pad member  15   d  has an approximately rectangular plate shape, includes a urethane rubber or similar elastic member, and is formed so that the width of the multipurpose separation pad  15   b  is smaller than the width of the paper  3 . In other words, the multipurpose separation pad  15   b  has a width that provides contact with only the widthwise center part of the paper  3  for feeding the paper  3 .  
         [0099]     Then the topmost paper  3  stacked in the multipurpose tray  14  is pinched between the multipurpose paper feed roller  15   a  and the multipurpose separation pad  15   b  by the rotation of the multipurpose paper feed roller  15   a,  and is separated and fed one sheet at a time by the cooperative action of the multipurpose paper feed roller  15   a  and the multipurpose separation pad  15   b.    
         [0100]     The paper  3  fed from the multipurpose tray  14  passes through the second transportation path  44 , and is transported to the second transportation section  10 . At this time, as described above, the paper  3  is transported by being pinched between the second transportation roller  10   a  and the second paper dust removing roller  10   b,  and the surface opposite to the image formation surface comes into contact with the roller  10   g  of the second paper dust removing roller  10   b.  At this time, since the second paper dust removing roller  10   b  is slightly wider than the width of the multipurpose separation pad  15   b,  paper dust generated with a width approximately equal to the width of the multipurpose separation pad  15   b  on the paper  3  due to friction with the multipurpose separation pad  15   b  is scraped off and electrostatically adsorbed by the roller  10   g.  Then, when the paper dust adhering to the roller  10   g  next confronts the second sponge member  10   c  through the rotation of the second paper dust removing roller  10   b,  the paper dust is scraped off by the second sponge member  10   c,  and falls into and is accumulated in the storage tank  71 .  
         [0101]     As described above, paper dust generated with a width approximately equal to the width of the multipurpose separation pad  15   b  on the paper  3  due to friction with the multipurpose separation pad  15   b  is removed satisfactorily from the surface of the paper  3  in the second transportation section  10 .  
         [0102]     Subsequently, the paper  3  passes further through the transportation path  46 , and is transported to the third transportation section  11 . At this time, as described above, paper dust originally generated on the entirety of the paper  3  during cutting of the paper  3  and so forth is scraped off and electrostatically adsorbed by the roller  11   g  of the third paper dust removing roller  11   b.  Then, when the paper dust adhering to the roller  11   g  next confronts the third sponge member  11   c  through the rotation of the third paper dust removing roller  11   b,  the paper dust is scraped off by the third sponge member  11   c.  The scraped-off paper dust is received by the receiving surface  61 , and then, through the rotation of the auger member  62  ( FIG. 4 ), is transported to the both ends of the axial direction (in the directions of the arrow X and the arrow Y) of the third paper dust removing roller  11   b  by the first spiral member  64  and the second spiral member  65 , and is dropped into and accumulated in the storage tank  71  located below the third transportation section  11 .  
         [0103]     Accordingly, paper dust originally generated on the entirety of the paper  3  during cutting of the paper  3  and so forth is removed satisfactorily from the surface of the paper  3  in the third transportation section  11 .  
         [0104]     According to the present embodiment, paper dust can be removed across the entire width of the paper  3  whichever transportation path the paper  3  passes through. Therefore, image quality degradation caused by paper dust on the paper  3  is less likely to occur. Also, as paper dust can be removed from parts in contact with the separation pad  13  whichever transportation path the paper  3  passes through, image quality degradation caused by paper dust on the paper  3  is less likely to occur.  
         [0105]     Moreover, as paper dust adhering to the paper  3  that has passed through the reverse transportation path  41  can be removed, when images are formed on both sides, quality degradation caused by paper dust on the paper  3  is less likely to occur for both side.  
         [0106]     Further, the paper  3  fed from the paper supply cassette  4  passes through the first transportation section  9  provided with the first paper dust removing roller  9   b,  the second transportation section  10  provided with the second paper dust removing roller  10   b,  and the third transportation section  11  provided with the third paper dust removing roller  11   b,  along the first transportation path  43 . Thus, the paper dust on the paper  3  passing through the first transportation path  43  is thoroughly removed, and quality degradation of images caused by paper dust on the paper  3  is less likely to occur. On the other hand, the paper  3  fed from the multipurpose tray  14  passes through the second transportation section  10  provided with the second paper dust removing roller  10   b  and the third transportation section  11  provided with the third paper dust removing roller  11   b,  along the second transportation path  44 . Thus, the paper dust on the paper  3  passing through the second transportation path  44  is thoroughly removed, and quality degradation caused by the paper dust is less likely to occur.  
         [0107]     Further, the storage tank  71  that holds paper dust is disposed inside the closed path that is partly formed by the reverse transportation path  41 , and is located below the second transportation section  10  and the third transportation section  11 . Thus, because it is not necessary to provide two separate storage tanks for the second transportation section  10  and the third transportation section  11 , a space can be used effectively, and the laser printer  1  can be made smaller. In addition, costs can be reduced through a reduction in the number of component parts.  
         [0108]     In the above-described embodiment, the storage tank  71  is located below the second transportation section  10  and the third transportation section  11 , and can hold dust scraped off and dropped by both the second paper dust removing roller  10   b  and the third paper dust removing roller  11   b.  However, tanks may be provided separately for the second transportation section  10  and the third transportation section  11 .  
         [0109]     While the invention has been described in detail with reference to the specific embodiment thereof, it would be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention.  
         [0110]     For example, the above-described embodiment relates to a laser printer. However, the present invention is not limited to a laser printer and can also be applied to different types of printers such as an ink-jet type printer, an image reading device, or another device having the same kind of transportation paths as the above-described embodiment.  
         [0111]     Further, in the above-described embodiment, the laser printer  1  has a reverse transportation path. However, the laser printer may be a printer that does not have a reverse transportation path.