Abstract:
A paper stacking unit and an image forming apparatus having the same, the paper stacking unit including: a base frame supporting a print media, a cover pivotally connected to the base frame and supporting the print media together with the base frame, and a plate connected to the cover for auxiliarily supporting the print media.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION  
       [0001]     This application claims the benefit of Korean Patent Application No. 10-2005-0018134, filed on Mar. 4, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     Aspects of the present invention relate to an image forming apparatus, and more particularly, to an image forming apparatus with a print media stacking unit for stacking multiple sheets of print media.  
         [0004]     2. Description of the Related Art  
         [0005]     In general, an image forming apparatus prints a desired image by: forming an electrostatic latent image on a photosensitive medium using an exposing unit, such as laser scanning unit, in response to a digital image signal; developing a toner image by supplying a toner to the electrostatic latent image; transferring the toner image onto a print medium; and fixing the toner image on the print medium by applying heat and pressure to the toner image.  
         [0006]     Image forming apparatuses are classified into a dry type and a wet type according to a state of a toner and carrier used. The wet-type dry image forming apparatuses are also classified into two types: an apparatus having a one-phase developing device, and an apparatus having a two-phase developing device.  
         [0007]     The one-phase developing device forms an image by supplying only a toner to the electrostatic latent image, while the two-phase developing device forms an image by supplying a carrier mixed with toner particles to the electrostatic latent image.  
         [0008]     With regard to the one-phase developing device, after the toner is applied onto a photosensitive medium to develop a toner image, the toner left on a surface of the photosensitive medium is removed by a cleaning blade, and is recovered by a recovery unit to recycle the toner.  
         [0009]     With regard to the two-phase developing device, the carrier is not supplied to the photosensitive medium, though it is still reused. However, after only toner particles are supplied onto the photosensitive medium to develop the toner image, the toner particles left on a surface of the photosensitive medium are removed by a cleaning blade, and recovered by a recovery unit to recycle the toner.  
         [0010]     Multifunction peripherals combining both scanning and printing operations have been widely utilized. A multi-function peripheral includes a scanning unit and a printing unit. The scanning unit is disposed on an upper portion of the printing unit, and scans a document and inputs an image of the document to the printing unit. The printing unit receives a digital image signal corresponding to the image of the document inputted from the scanning unit, and prints an image corresponding to the image onto a print medium.  
         [0011]     However, due to the multi-functional quality of the peripheral, this apparatus has a large size. Thus, to reduce the size of the apparatus, a size of the print media stacking unit must be decreased since the size of the main components for scanning/printing are difficult to reduce.  
       SUMMARY OF THE INVENTION  
       [0012]     According to an aspect of the present invention, there is provided an image forming apparatus with a print media stacking unit detachably mounted to a body of the image forming apparatus, the print media stacking unit having a variable length corresponding to a size of the print media.  
         [0013]     The print media stacking unit comprises: a base frame for supporting a print media; a cover pivotally connected to the base frame and supporting the print media together with the base frame; and a plate coupled to the cover for auxiliarily supporting the recording medium.  
         [0014]     Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:  
         [0016]      FIG. 1  is a perspective view of an image forming apparatus having a print media stacking unit according to an embodiment of the present invention;  
         [0017]      FIG. 2  is a cross-sectional view schematically illustrating the image forming apparatus shown in  FIG. 1 ;  
         [0018]      FIG. 3  is a perspective view illustrating a state in which the print media stacking unit shown in  FIG. 1  is detached from a body of the image forming apparatus;  
         [0019]      FIG. 4  is a perspective view illustrating the print media stacking unit of  FIG. 1 ; and  
         [0020]      FIG. 5  is a perspective view illustrating a cover and a plate of the print media stacking unit shown in  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0021]     Reference will now be made in detail to the present embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.  
         [0022]     Referring to  FIGS. 1, 2 ,  3 , and  4 , an image forming apparatus according to an embodiment of the present invention includes a printing section  10 , a scanning section  80 , and a delivery section  73  disposed between the printing section  10  and the scanning section  80  for delivering a print medium with a toner image fixed thereon.  
         [0023]     The printing section  10  prints an image on the print medium, and includes a print media stacking unit  20 , a developing unit  30 , a transfer roller  32 , a fixing unit  60 , and a delivery unit  70 .  
         [0024]     The print media stacking unit  20  is detachably provided under a body  1  of the image forming apparatus to stack sheets of print media therein. A pickup roller  21  is provided above the print media stacking unit  20  to pick up the print media one sheet at a time. The print medium picked up by the pickup roller  21  is transferred along a transfer path, and is delivered to the delivery section  73  through a transferring and fixing process of the image.  
         [0025]     The print media stacking unit  20  includes a base frame  22 , a cover  23 , and a plate  24 . The base frame  22 , the cover  23 , and the plate  24  are connected to each other to support the print media.  
         [0026]     The base frame  22  is detachably mounted to the body  1  to support the print media. Guide bosses  223  for guiding an operation of attaching/detaching the base frame  22  to/from the body  1  are provided on both sides of the base frame  22 . The base frame  22  has a knock-up plate  221  for pushing the print media upward, and a print media width guide  222  sliding to the left and right according to a width of the print media and supporting the print media.  
         [0027]     The base frame  22  has a connecting portion  224  connected to the cover  23 , and a pivot restricting portion  226  for restricting the movement of the cover  23  within a range of an acute angle.  
         [0028]     A plurality of the connecting portions  224  are provided at a rear side of the base frame  22  at regular intervals, each connecting portion having a connecting boss  225  which is inserted into a hole  231  formed in the cover  23 .  
         [0029]     The pivot restricting portion  226  is provided at a rear side of the base frame  22  to support and restrict the rotation of the cover  23 . The pivot restricting portion  226  is disposed between the connecting portions  224 .  
         [0030]     The cover  23  is pivotally attached to the base frame  22  to support a portion of the print media. When the cover  23  is vertically folded to the base frame  22 , the cover  23  covers a front surface of the body  1 . Meanwhile, when the cover  23  is unfolded from the base frame  22 , the cover  23  accommodates the print media, as shown in  FIG. 5 .  
         [0031]     The plate  24  is slidably attached to the cover  23 , as shown  FIG. 3 , or is pivotally attached to the cover  23 , as shown in  FIG. 4 .  
         [0032]     The developing unit  30  includes a photosensitive drum  31 . An electrostatic latent image is formed on a surface of the photosensitive drum  31  charged to a desired potential by irradiating light from an exposing unit  40  (for example, a laser scanning unit). The photosensitive drum  31  is oppositely in contact with the transfer roller  32 , when the print medium passes between them. The developing unit  30  is filled with a toner supplied to the photosensitive drum  31  to develop the electrostatic latent image as the toner image.  
         [0033]     The transfer roller  32  presses the print medium, which passes between the photosensitive drum  31  and the transfer roller  32 , against the photosensitive drum  31  with a predetermined pressure, so as to transfer the toner image formed on the photosensitive drum  31  onto the print medium.  
         [0034]     The fixing unit  60  applies heat and pressure to the toner image transferred onto the print medium to fix the toner image onto the print medium, while the print medium passes between the photosensitive drum  31  and the transfer roller  32 .  
         [0035]     The delivery unit  70  delivers the print medium with the toner image fixed thereon by the fixing unit  60  to the delivery section  73 .  
         [0036]     The scanning section  80  is disposed on the body  1  to irradiate light onto a document (not shown) to scan a document, and includes a scanning frame  81  fixed to the upper portion of the body  1 , and a cover  85  pivotally attached to the scanning frame  81 .  
         [0037]     A glass plate  84  is disposed on the scanning frame  81 , and an image sensor  83  is slidably disposed below the glass plate to scan the document (not shown) placed flat on the glass plate  84  and to input a digital signal corresponding to the document.  
         [0038]     The delivery unit  70  includes a delivery roller  71  rotatably supported on a delivery guide rib  2 , and a delivery idler roller  72  rotatably supported on a delivery idler guide rib  3  and in contact with the delivery roller  71 .  
         [0039]     When the print medium picked up from the print media stacking unit  20  passes through the developing unit  30  and the fixing unit  60 , the electrostatic latent image is developed on the print medium as the toner image. After the toner mage is fixed on the print medium, the print medium passes through the delivery roller  72  and the delivery idler roller  72 , and is discharged and stacked on the delivery section  73 .  
         [0040]     The print media stacking unit according to the present invention has the following advantages.  
         [0041]     First, since the print media stacking unit is detachably mounted in the body of the apparatus and supports the print media, the space occupied by the image forming apparatus can be reduced.  
         [0042]     Second, since the cover can be replaced by a cover of a different color, the aesthetic design of the apparatus can be improved.  
         [0043]     Finally, misfeeding of the print media due to slippage thereof can be prevented by restricting the movement of the cover within a range of an acute angle.  
         [0044]     Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.