Abstract:
A conveying apparatus includes a conveying unit that includes a conveying passage for conveying a conveyed material, and a positioning and holding unit that holds the conveying unit while positioning the conveying unit. The positioning and holding unit includes a plate-shaped member having at least one protruding portion, the plate-shaped member constitutes a part of the conveying passage, and the at least one protruding portion protrudes towards the conveying passage which the conveyed material passes through.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2006-271632 filed Oct. 3, 2006. 
     BACKGROUND 
     Technical Field 
     The present invention relates to a conveyed material conveying apparatus, an image forming apparatus, a conveying method, and an image forming method. 
     SUMMARY 
     According to an aspect of the invention, there is provided a conveying apparatus including: a conveying unit that comprises a conveying passage for conveying a conveyed material; a positioning and holding unit that holds the conveying unit while positioning the conveying unit, wherein the positioning and holding unit comprises a plate-shaped member having at least one protruding portion, the plate-shaped member constituting a part of the conveying passage, and the at least one protruding portion protruding towards the conveying passage which the conveyed material passes through. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the present invention will be described in detail based on the following figures, wherein: 
         FIG. 1  illustrates a drawing showing an image forming apparatus of a first exemplary embodiment of the invention; 
         FIG. 2  illustrates a perspective view showing a support member of the image forming apparatus of the first exemplary embodiment; 
         FIGS. 3A to 3C  illustrate drawings showing a bottom plate of the support member of the image forming apparatus of the first exemplary embodiment; 
         FIG. 4  illustrates a perspective view showing a support member of an image forming apparatus of a second exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, exemplary embodiments of the invention will be described by reference to the accompanying drawings. 
     First Exemplary Embodiment 
       FIGS. 1 to 3C  are drawings which show a first exemplary embodiment of an image forming apparatus according to an aspect of the invention. 
       FIG. 1  is a diagram showing an image forming apparatus  100  in this embodiment. The image forming apparatus  100  has an image input unit  1  for optically reading image information of a document  11  placed on a platen  10  and converting the image information so read into electrical image data by a CCD sensor  12  and an image output unit  2  (an image forming unit) that forms an image on a sheet P (a recording medium) based on the image data transferred from the image input unit  1 , and furthermore, the image forming apparatus  100  has an automatic document feeder  13  for automatically feeding a document  11  on to the platen  10 . 
     The image output unit  2  forms a toner image on a light-sensitive material drum  20  based on the image data transferred from the image input unit  1 , and thereafter transfers the toner image on to a sheet P, so as to form a recorded image on the sheet P. The sheet P on which the toner image is transferred is discharged on to a discharge tray  50  via a fixing unit  4 . 
     In addition, the light-sensitive material drum  20  of the image output unit  2  rotates at a predetermined processing speed in a direction indicated by an arrowed line, and arranged on the periphery of the light-sensitive material drum  20  are a charging corotron  21  for uniformly charging a surface of the light-sensitive material drum  20  up to a predetermined background potential, a laser beam scanner  22  for exposing the light-sensitive material drum  20  with a laser beam which is modulated based on the image data so as to form an electrostatic latent image on the light-sensitive material drum  20 , a developing unit  23  for developing the electrostatic latent image on the light-sensitive material drum  20 , a pre-transfer processing corotron  24  for removing the potential on the light-sensitive material drum  20  prior to the transfer of the toner image on to the sheet P, and a cleaner  25  that removes residual toner on the light-sensitive material drum  20  after the completion of transfer of the toner image. Note that in the figure, reference numeral  26  denotes a toner cartridge which contains toner that is to be supplied to the developing unit  23 . Note that the components that have been described above are constituent components of the image output unit  2 . 
     On the other hand, a conveying belt  3  that conveys a sheet P is wound round a driving roller and a follower roller in such a manner as to be extended therebetween and rotates in a direction indicated by an arrowed line, and a toner image formed on the light-sensitive material drum  20  is designed to be transferred on to a sheet P which is conveyed thereto by the conveying belt  3 . An image transfer roller  30  that forms a transfer electric field between the light-sensitive material drum  20  and itself is provided in a position which faces the light-sensitive material drum  20  across the conveying belt  3 . In addition, a belt cleaner  33  is provided in a predetermined position along the conveying belt  3  for removing paper dust and/or residual toner from the surface of the conveying belt  3 . Note that the components that have been described above are constituent components of the conveying belt  3 . 
     In addition, a sheet feeding unit  5  that feeds a sheet P to the image output unit  2  is provided below the image output unit  2 . Four sheet feeding trays  5   a  to  5   d  are equipped in the sheet feeding unit  5  which store sheets P in different sizes. In addition, in the sheet feeding unit  5 , pick-up rollers  51  that convey topmost sheets stored in the individual sheet feeding trays  5   a  to  5   d  towards the image output unit  2  are provided in order to convey sheets P to the image output unit  2  a sheet at a time, and feed rollers  52   a  and retarder rollers  52   b  are provided downstream of the pick-up rollers  51  in the direction in which sheets P are conveyed as double-sheet protectors which prevent a plurality of sheets P from being fed in a superposed fashion to the image output unit  2  by the pick-up rollers  51 . In addition, a plurality of conveying rollers  53  are provided in the sheet feeding unit  5  along a conveying path of sheets P extending from the individual sheet feeding trays  5   a  to  5   d  to a toner image transferring position. Additionally, registration rollers  54  are provided just before the image transferring position in the sheet feeding unit  5 . The registration rollers  54  convey sheets P conveyed from the sheet feeding trays  5   a  to  5   d  to the image transferring position at a predetermined timing which is in synchronism with a writing timing at which an electrostatic latent image is written on to the light-sensitive material drum  20 . 
     In addition, a sheet feeding device  55  is provided at one side end portion of the image forming apparatus  100  for feeding sheets P from an exterior portion of the image forming apparatus  100  into an interior of the image forming apparatus  100 . The sheet feeding device  55  is made up of a tray  56  on which sheets P are placed and a feeding unit  57  that feeds sheets P placed on the tray  56  into the interior of the image forming apparatus  100  a sheet at a time. The sheet feeding unit  57  includes a pick-up roller  58  that conveys a topmost sheet of the sheets P placed on the tray  56  towards the interior of the image forming apparatus  100 , as well as a feed roller  59   a  and a retarder roller  59   b  as a double-sheet protector which prevents a plurality of sheets P from being conveyed in a superposed fashion towards the interior of the image forming apparatus  100  by the pick-up roller  58 , the feed roller  59   a  and the retarder roller  59   b  being provided downstream of the pick-up roller  58  in the direction in which sheets P are conveyed. 
     In addition, a reverse discharge unit  6  is disposed between the fixing unit  4  and the discharge tray  50  for reversing a sheet P discharged from the fixing unit  4  so as to be discharged on to the discharge tray  50 . A reverse conveying passage  60  is formed in the reverse discharge unit  6 . The reverse conveying passage  60  is made up of a primary reverse discharge passage  62  for drawing a sheet P discharged from the fixing unit  4  thereinto and a secondary reverse discharge passage  64  for reversing the conveying direction of the sheet P so drawn in to discharge the sheet P on to the discharge tray  50 . Conveying rollers  65  are provided on the primary reverse discharge passage  62 . Conveying rollers  66  are provided on the secondary reverse discharge passage  64 . In addition, discharge rollers  67  are provided just before the discharge tray  50 . 
     In addition, a reverse conveying unit  7  is disposed below the image output unit  2  and above the sheet feeding trays  5   a  to  5   d  in the sheet feeding unit  5  for reversing a sheet P on one side of which an image is formed by the image output unit  2  to convey the sheet P so reversed back to the image output unit  2  for an image to be formed on the other side thereof for double-side image formation. A reverse conveying passage  70  is formed in the reverse conveying unit  7 . The reverse conveying passage  70  is made up of a primary reverse discharge passage  72  for drawing a sheet P discharged from the fixing unit  4  thereinto and a secondary reverse discharge passage  74  for reversing the conveying direction of the sheet P so drawn in to discharge the sheet P to the image output unit  2 . Conveying rollers  75  are provided on the primary reverse discharge passage  72 . In addition, discharge rollers  76  are provided on the secondary reverse conveying passage  74 . 
     In addition, conveying rollers  68  are provided upstream of the registration rollers  54  in the sheet feeding unit  5  for conveying sheets P conveyed from the sheet feeding trays  5   a  to  5   d , the sheet feeding device  55  and the reverse conveying unit  7  to the registration roller  54 . 
     Note that the image output unit  2 , the conveying belt  3 , the fixing unit  4 , part of the sheet feeding unit  5 , the reverse discharge unit  6  and the reverse conveying unit  7  are supported on a support member  8  (a support unit). In addition, the conveying belt  3 , the fixing unit  4 , the part of the sheet feeding unit  5 , the reverse discharge unit  6  and the reverse conveying unit  7  (a drawer unit U) are supported on sliding rails  81 ,  82  which are provided slidably relative to the support member  8  in such a manner as to be drawn out to the front of the apparatus. 
     In the image forming apparatus  100  of the exemplary embodiment which is configured as has been described heretofore, the laser beam scanner  22  exposes the light-sensitive material drum  20  based on image information on a document which is captured by the image input unit  1 , and an electrostatic latent image matching the image information is written on to the light-sensitive material drum  20 . This electrostatic latent image is developed by the developing unit  23  at a timing which is slightly later than the writing timing. Then, a toner image, which is formed in this way, is transferred on to a sheet P which is conveyed from the registration rollers  54  by the image transfer roller  30  at a predetermined timing, and the sheet P on which the unfixed toner image is transferred is discharged on to the discharge tray  50  via the fixing unit  4 . 
     Note that the sheet P, whose unfixed image has been fixed by the fixing unit  4 , is conveyed to the reverse discharge unit  6  so as to be reversed thereby for discharge on to the discharge tray  50 . 
     In addition, the sheet P, whose unfixed toner image formed on one side thereof has been fixed by the fixing unit  4 , is conveyed to the reverse conveying unit  7  so as to be reversed to be conveyed back to the image output unit  2  for an image to be formed on the other side thereof for double-side image formation and is then discharged on to the discharge tray  50 . 
       FIG. 2  is a perspective view showing the support member  8  of the image forming apparatus  100  of the exemplary embodiment. The support member  8  is formed into a box-like shape which is opened at the front thereof and supports the image output unit  2 , the conveying belt  3 , the fixing unit  4 , the part of the sheet feeding unit  5 , the reverse discharge unit  6  and the reverse conveying unit  7 . A bottom plate  84  is provided at a bottom portion of the support member  8 . The bottom plate  84  of the support member  8  constitutes the primary reverse conveying passage  72  of the reverse conveying unit  7 . 
       FIGS. 3A to 3C  show drawings depicting the bottom plate  84  of the support member  8  of the image forming apparatus  100  of the exemplary embodiment.  FIG. 3A  is a plane view of the bottom plate  84 .  FIG. 3B  is a side view of the bottom plate  84 .  FIG. 3C  is a sectional view taken along the line A-A in  FIG. 3A . 
     The bottom plate  84  is formed substantially into a rectangular shape. A plurality of (in this exemplary embodiment, six) protruding portions  86  are formed on the bottom plate  84 . The height of the protruding portions  86  is, for example, 2 mm or more and 6 mm or less. The protruding portions  86  are formed in a central portion of the bottom plate  84  which excludes edge portions thereof. The protruding portions  86  are formed in such a manner as to extend in a direction which intersects the direction in which sheets P are conveyed substantially at right angles. The length L of the protruding portions  86  in a direction in which the protruding portions  86  extend is made longer than the width of a sheet P whose size is the largest in sheets used in the image forming apparatus  100 , the width of the sheet P being defined as extending in a direction which intersects the direction in which sheets are conveyed substantially at right angles. In addition, the protruding portion  86  is formed in such a manner as to be inclined at a predetermined angle θ from a base portion to an apex portion thereof in a direction in which sheets P enter the primary reverse conveying passage  72 . The predetermined angle θ is, for example, 10° or more and 20° or less. The protruding portions  86  are formed at predetermined intervals W according to lengths of a plurality of types of sheets P in the direction in which sheets P are conveyed. The plurality of types of sheets include, for example, sheets of a size of regular post cards, B5-size sheets, A4-size sheets, B4-size sheets and A3-size sheets. The predetermined interval W is an interval which enables a sheet P to stride across one or more intervals between the protruding portions  86  when the sheet P is drawn into the primary reverse conveying passage  72 . 
     In addition, a member (not shown) is provided in such a manner as to be located to match positions between the protruding portions  86  for removing a sheet jam in association with an operation of drawing out the drawer unit in the event that a jam of a sheet or sheets P occurs in the primary reverse conveying passage  72 . 
     Second Exemplary Embodiment 
     Next, a second exemplary embodiment of an image forming apparatus according to an aspect of the invention will be described. 
       FIG. 4  is a perspective view showing a support member  9  of an image forming apparatus of this exemplary embodiment. The image forming apparatus of this exemplary embodiment is such that the support member  8  of the image forming apparatus  100  of the first exemplary embodiment is replaced by the support member  9 . The support member  9  in this exemplary embodiment is such that the bottom plate  84  of the support member  8  of the first exemplary embodiment is replaced by a bottom plate  94 . 
     The bottom plate  94  is formed substantially into a rectangular. A protruding portion  96  is formed on an upstream side of the bottom plate  94  in a direction in which a sheet P enters a primary reverse conveying passage  72  in such a manner as to extend in a direction which intersects substantially at right angles a direction in which sheets P are conveyed. The length L of the protruding portion  96  in a direction in which the protruding portion  96  extend is made longer than the width of a sheet P whose size is the largest in sheets used in the image forming apparatus, the width of the sheet P being defined as extending in a direction which intersects the direction in which sheets are conveyed substantially at right angles. In addition, the protruding portion  96  is formed in such a manner as to be inclined at a predetermined angle θ from a base portion to an apex portion thereof in a direction in which sheets P enter the primary reverse conveying passage  72 . In addition, a plurality of protruding portions  97  are formed on the bottom plate  94  in such a manner as to expand at predetermined angles and over predetermined lengths in a V-shaped fashion in the direction in which sheets P enter the primary reverse conveying passage  72 . The protruding portions  97  are formed in such a manner as to become substantially symmetrical with each other at centers of V-shapes relative to a straight line which passes through a substantially central portion of a direction which intersects at right angles the direction in which sheets P are conveyed. In addition, distal end portions of the protruding portions  97  in the direction in which sheets P are conveyed are each formed into a circular arc shape. The protruding portion  96  and the protruding portions  97  are formed at predetermined intervals W according to lengths of a plurality of types of sheets P in the direction in which sheets P are conveyed. The plurality of types of sheets include, for example, sheets of a size of regular post cards, B5-size sheets, A4-size sheets, B4-size sheets and A3-size sheets. The predetermined interval W is an interval which enables a sheet P to stride across one or more intervals between the protruding portion  96  and the protruding portions  97  when the sheet P is drawn into the primary reverse conveying passage  72 . In addition, the protruding portion  96  and the protruding portions  97  are formed at a central portion of the bottom plate  94  which excludes edge portions thereof. Recessed portions  98 ,  99  are formed at both edge portions of the bottom plate  94  in a direction which intersects at right angles the direction in which sheets P are conveyed. 
     In addition, a member (not shown) is provided in such a manner as to be located to match positions between the protruding portion  96  and the protruding portions  97  for removing a sheet jam in association with an operation of drawing out the drawer unit in the event that a jam of a sheet or sheets P occurs in the primary reverse conveying passage  72 . 
     Note that the invention is not limited to the embodiments that have been described heretofore but can be modified variously without departing from the spirit and scope of the invention. For example, while the exemplary embodiments are described as the bottom plate of the support member being used as a bottom surface of the reverse conveying passage of the reverse conveying unit, a side plate and a top plate of the support member can be used as a side surface and a top surface of the reverse conveying passage, respectively, or the bottom plate of the support member may be used not as part of the reverse conveying unit but as part of a non-reverse conveying unit. In addition, the support member does not denote only a member which is related to the whole of the apparatus but includes so-called subframe, unit frame and the like which support some of the constituent components of the apparatus. 
     While in the exemplary embodiments, as a sheet-shaped conveyed material conveying apparatus to which the invention can be applied, the so-called digital copier is raised which installs thereon the image reading apparatus based on the xerography method, the invention can be applied to image forming apparatuses which utilize methods other than the xerography such as the ink-jet method, and the invention can also be applied to a printer without an image reading apparatus. In addition, the invention can also be applied to a sheet feeding apparatus and a post-processing apparatus which are provided as options to an image forming apparatus. 
     The foregoing description of the exemplary embodiments of the present invention has been provided for the purpose of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The exemplary embodiments are chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various exemplary embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.