Patent Publication Number: US-2007120319-A1

Title: Paper feeding cassette

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application claims the benefit under 35 U.S.C. § 119 (a) of Korean Patent Application No. 2005-113568 filed on Nov. 25, 2005, the entire content of which is incorporated herein by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present general inventive concept relates to a paper feeding device to feed a printing medium into an image forming apparatus. More particularly, the present general inventive concept relates to a paper feeding cassette of a paper feeding device.  
      2. Description of the Related Art  
      An image forming apparatus, such as a copier, a printer and a facsimile, for forming a certain image on a printing medium may typically be classified as an electrophotographic type that uses a photosensitive body, an inkjet type that directly ejects a developer onto the printing medium, a thermal transfer type, a bubble jet type, a dye sublimation type, a dot matrix type, etc.  
      Since digital cameras have recently gained widespread popularity, an increased number of users desire to directly output an image photographed by a digital camera onto the printing medium as well as store the image in a storage medium such as a hard disk drive. To this end, a photo printer has been developed. The photo printer is a printer that is dedicated to printing digital photos from images stored in the digital camera connected by a PictBridge, or that prints images stored in a memory card. The photo printer may be classified as the bubble jet type, the thermal transfer type, and the dye sublimation type.  
      The photo printer is designed to have a compact size so that it is portable and easy to carry and a photographed image can be directly printed at an outdoor place. The printing medium includes a special paper dedicated to printing a photo (i.e., photo paper), and the size of the photo paper is typically either 4×6 inches or A4 size.  
      The image forming apparatus has a paper feeding device which supplies a printing medium such as a paper into the image forming apparatus. The paper feeding device includes a paper feeding cassette having a plurality of printing medium (i.e., sheets) stacked therein and a pick-up unit to pick up the printing medium sheet by sheet from the paper feeding cassette to feed the printing medium into a printing part of the image forming apparatus.  
      The paper feeding cassette is detachably mounted to the image forming apparatus such that the plurality of sheets of printing medium can be easily stacked in the paper feeding cassette.  
      When stacked in the paper feeding cassette, the plurality of sheets of printing medium should be accurately aligned therein. If the printing medium stacked in the paper feeding cassette is not accurately aligned, various errors occur when the image forming apparatus performs printing or the printing medium is fed. These errors result in a paper jam or a curl of the printing medium.  
      Accordingly, it is very important to align the printing medium stacked in the paper feeding cassette in order to increase the operability and durability of the image forming apparatus.  
      The alignment of the printing medium in the paper feeding cassette is especially important for an image forming apparatus such as the photo printer which uses a high-priced paper dedicated to printing photos (e.g., the photo paper), or an image forming apparatus from which a paper feeding cassette can be separated such that the image forming apparatus has a compact size.  
     SUMMARY OF THE INVENTION  
      Accordingly, the present general inventive concept provides a paper feeding cassette which can perform an accurate picking-up operation so that a stable image quality can be obtained.  
      The present general inventive concept also provides a paper feeding cassette which can easily and accurately align sheets of a printing medium.  
      The present general inventive concept also provides a paper feeding cassette to prevent sheets of a printing medium from overlapping when being picked up, not by an individual sheet such that the printing medium can be properly picked up from a paper feeding cassette.  
      Additional aspects of the present general inventive concept 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 general inventive concept.  
      The foregoing and/or other aspects of the present general inventive concept are achieved by providing a paper feeding cassette including a cassette body detachably mounted to an image forming apparatus, and an alignment unit disposed on an inner surface of the cassette body to pressurize a plurality of stacked sheets of recording medium from one side thereof when the cassette body is mounted in the image forming apparatus.  
      The alignment unit may include at least one biasing member to be biased toward an inner space of the cassette body when the cassette body is mounted in the image forming apparatus.  
      The alignment unit may include a guide member to guide the biasing of the biasing member, and the guide member and the biasing member may be aligned to be movable relative to each other.  
      The biasing member may be formed at an inner surface of the cassette body to form a guide recess between the inner surface of the cassette body and the biasing member to receive the guide member therein. The biasing member may be formed of an elastic body having a first end fixed on the inner surface of the cassette body and a second end which is elastically biased toward the inner space of the cassette body, and the guide recess to receive the guide member is formed between the first and second ends of the biasing member.  
      The cassette body may have a reference surface at a first inner surface and an alignment unit at a second surface opposite to the reference surface.  
      The reference surface may have a plurality of contacting surfaces protruding toward an inner space of the cassette body by the same lengths.  
      The paper feeding cassette may further include a cover slidingly disposed at a top portion of the cassette body.  
      The guide member may be fixedly connected to the cover.  
      The cover and the cassette body may include a guide protrusion and a guide groove at a contacting portion therebetween.  
      The cover may further include an elastic rib to elastically pressurize a top side of the sheets of recording medium stacked in the cassette body.  
      The cassette body may further include a protrusion portion at the top portion to incline the cover at a slight angle when the cassette body is mounted in the image forming apparatus.  
      The foregoing and/or other aspects of the present general inventive concept are achieved by providing a paper feeding cassette usable in an image forming apparatus, the cassette including a cassette body to accommodate recording media and being mountable in a mounting part of the image forming apparatus, and an alignment unit disposed on a side of the cassette body to push the recording media against a reference surface in the cassette body as the cassette body is being mounted in the mounting part.  
      The foregoing and/or other aspects of the present general inventive concept are achieved by providing a paper feeding cassette usable in an image forming apparatus, the cassette including a body having top and bottom portions slideably coupled to one another to accommodate sheets of recording media therebetween, and an alignment unit having complementary projecting parts disposed on the top and bottom portions of the body such that the complementary projecting parts engage each other as the top and bottom portions are moved with respect to each other into a mounting position such that the engagement of the complementary projecting parts pushes the recording media into an aligned position.  
      The foregoing and/or other aspects of the present general inventive concept are achieved by providing a paper feed cassette, including a tray part to accommodate sheets of printing media and having a biasing member extending along an inner sidewall thereof, and a cover part coupled to the tray part and having a guide member extending from a side bottom portion thereof such that the biasing member engages the guide member when the cover part is moved with respect to the tray part into a mounting position.  
      The foregoing and/or other aspects of the present general inventive concept are achieved by providing a paper cassette mountable in an image forming apparatus, the cassette including a bottom part to accommodate printing media, and a top part movably coupled to the bottom part between a first position with respect to the bottom part when the cassette is dismounted from the image forming apparatus, and a second position with respect to the bottom part when the cassette is mounted in the image forming apparatus.  
      The foregoing and/or other aspects of the present general inventive concept are achieved by providing an image forming apparatus including a paper feeding cassette having a body with top and bottom portions slideably coupled to one another to accommodate sheets of recording media therebetween, and an alignment unit having complementary projecting parts disposed on the top and bottom portions of the body such that the complementary projecting parts engage each other as the top and bottom portions are moved with respect to each other into a mounting position such that the engagement of the complementary projecting parts pushes the recording media into an aligned position. The image forming apparatus further includes a mounting part having a receiving space to receive the paper feeding cassette into the mounting position.  
      The foregoing and/or other aspects of the present general inventive concept are achieved by providing an image forming apparatus, including a mounting part and a paper cassette mountable in the mounting part. The cassette includes a body to accommodate recording media therein, and a cover slidably coupled to the body to cover the recording media and to slide from a first end of the body to a second end of the body as the cassette is inserted in the mounting part. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      These and/or other aspects of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:  
       FIG. 1  is a perspective view illustrating a paper feeding cassette in a state in which the paper feeding cassette is not mounted in an image forming apparatus, according to an embodiment of the present general inventive concept;  
       FIG. 2  is a perspective view illustrating the paper feeding cassette of  FIG. 1  in a state in which the paper feeding cassette is mounted in an image forming apparatus, according to an embodiment of the present general inventive concept;  
       FIG. 3A  is a transverse cross-sectional view illustrating the paper feeding cassette of  FIG. 1  in the state in which the paper feeding cassette is not mounted in the image forming apparatus, according to an embodiment of the present general inventive concept;  
       FIG. 3B  is an enlarged view illustrating an alignment unit of the paper feeding cassette of  FIG. 3A  at reference point IIIA;  
       FIG. 4A  is a transverse cross-sectional view illustrating the paper feeding cassette of  FIG. 1  in the state in which the paper feeding cassette is mounted in the image forming apparatus, according to an embodiment of the present general inventive concept;  
       FIG. 4B  is an enlarged view illustrating the alignment unit of the paper feeding cassette of  FIG. 4A  at reference point IVA;  
       FIG. 5  is a sectional side view illustrating the paper feeding cassette of  FIG. 1  along reference line V-V;  
       FIG. 6  is a sectional side view illustrating the paper feeding cassette of  FIG. 2  along reference line VI-VI; and  
       FIG. 7  is a perspective view illustrating a paper feeding cassette according to another embodiment of the present general inventive concept. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Reference will now be made in detail to the embodiments of the present general inventive concept, 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 general inventive concept by referring to the figures.  
       FIGS. 1 through 6  are views illustrating a paper feeding cassette according to an embodiment of the present general inventive concept.  
      As illustrated in FIGS.  1  to  6 , the paper feeding cassette includes a cassette body  10 , which has an inner space in which to stack a plurality of sheets of recording medium P. The cassette body  10  is detachably mounted in an image forming apparatus  100 .  
      Referring to  FIGS. 3A and 4A , a plurality of contacting surfaces  11  protrude toward the inner space of the cassette body  10  at one side thereof (e.g., the left side of  FIGS. 3A and 5 ). The contacting surfaces  11  have protruding lengths that are the same.  
      The plurality of contacting surfaces  11  protrude such that a friction force that occurs when the recording medium P contacts an entire side of the cassette body  10  can be decreased. In other words, the contacting surfaces  11  decrease an area of contact between the side of the cassette body  10  and the recording medium P. Therefore, a pick-up roller  55  (see  FIGS. 4A and 6 ) can more easily pick up the recording medium P.  
      An inside of the plurality of contacting surfaces  11  serves as a reference surface when the sheets of the recording medium P are aligned.  
      An alignment unit  20  is disposed at an opposite surface (i.e., the right side of  FIGS. 3 and 5 ) to the reference surface of the cassette body  10  to align the stacked sheets of recording medium P.  
      The alignment unit  20  includes a biasing member  22  and a guide member  21 . The biasing member  22  is biased toward the inner space of the cassette body  10  as the cassette body  10  is mounted to a mount part  110  of the image forming apparatus  100 , and the guide member  21  guides the biasing of the biasing member  22 .  
      As the biasing member  22  is biased toward the inner space of the cassette body  10  by the guide member  21 , the biasing member  22  presses one side of the recording medium P stacked in the cassette body  10  to align the widths of the sheets of the recording medium P against the reference surface defined by the contacting surfaces  11 .  
      The guide member  21  is aligned in a line with the biasing member  22  and is connected to the image forming apparatus  100  or a cover  30  of the paper feeding cassette.  
      The biasing member  22  and the guide member  21  are formed to be movable relative to each other. In other words, if the guide member  21  is fixed, the biasing member  22  is movable toward the guide member  21 , and if the biasing member  22  is fixed, the guide member  21  is movable toward the biasing member  22 .  
      The biasing member  22  may be formed of an elastic body having a first end  22   a  fixed to the inside of the cassette body  10  and a second end  22   b  which is elastically biased toward the inner space of the cassette body  10 . A guide recess  22   c  is formed between the first end  22   a  and the second end  22   b  to receive and guide a leading end of the guide member  21 .  
      A penetrating hole  18  of a predetermined size may be formed at a bottom surface of the cassette body  10  such that the recording medium P can be separated. For example, a user may insert and object or finger through the penetrating hole  18  to separate the sheets of recording medium P, which are stacked in the cassette body  10 .  
      The cover  30  is formed on a top surface of the cassette body  10  to prevent foreign material from outside the cassette body  10  from entering the cassette body  10 , and the cover  30  and the cassette body  10  are slidingly formed with respect to each other. Referring to  FIGS. 1 and 2 , the cover  30  may have an area to partially cover the top surface of the cassette body  10 . However, it should be understood that other types of covers may alternatively be used, and the cover  30  illustrated in FIGS.  1  to  3 A and  4 A to  6  is not intended to limit the scope of the present general inventive concept. For example, the cover  30  may have an area that fully covers the top surface of the cassette body  10 .  
      Referring to  FIGS. 3A and 4A , the sliding structure of the cover  30  and the cassette body  10  can be implemented using a guide protrusion  35  and a guide groove  15  which are formed at a contacting portion between the cover  30  and the cassette body  10  to correspond to each other.  
      In the present embodiment, the guide member  21  can be fixedly connected to a bottom surface of the cover  30 . Accordingly, the guide member  21  and the cover  30  move together in the same direction with each other. Since the cover  30  and the cassette body  10  slidingly engage with each other, the guide member  21  fixed on the cover  30  and the biasing member  22  fixed on the cassette body  10  also slidingly engage with each other. For example, the guide member  21  on the cover  30  may engage the biasing member  22  on the cassette body  10 , as the cassette body  10  is mounted in the mount part  110  of the image forming apparatus  100 .  
      Referring to  FIGS. 5 and 6 , an elastic rib  31  is formed at one side of the bottom surface of the cover  30  to be downwardly biased. A leading end portion of the elastic rib  31  presses an upper most sheet of the recording medium P stacked in the cassette body  10  to flatten the recording medium P.  
       FIG. 7  is a perspective view illustrating the paper feeding cassette according to another embodiment of the present general inventive concept. As illustrated in  FIG. 7 , the cover  30  may further include a pivot cover  40 , which is pivotably coupled to a front side of the cover  30 . Therefore, the sheets of the recording medium P can be more easily stacked into the cassette body  10  and foreign material from outside into the cassette body  10  can be more effectively prevented from entering the cassette body  10 .  
      Referring back to  FIGS. 5 and 6 , the cassette body  10  has protrusion portions  14 , which are curved with a predetermined radius, on top surfaces of opposite left and right sidewalls. When the cover  30  slides toward a front of the cassette body  10 , the cover  30  contacts the protrusion portions  14  to incline to a slight angle, and accordingly a pressurizing force of the elastic rib  31  is increased by the inclined angle.  
      Referring to  FIG. 3A , the mount part  110  of the image forming apparatus  100  into which the paper feeding cassette of the present embodiment is detachably mounted includes a receiving recess  111  to receive the cover  30  and a receiving space  112  to receive a rear side of the cassette body  10 .  
      A plurality of dams  113  are disposed at a rear side of the receiving space  112  to respectively sit in a plurality of penetrating openings  16  formed at the rear side of the cassette body  10 . Here, the dams  113  have general structures to prevent a feeding of overlapping sheets of the recording medium P, while the plurality of stacked sheets of recording medium P in the cassette body  10  are picked up by the pick-up roller  55  (see  FIGS. 4A and 6 ).  
      Referring to  FIGS. 3A and 4A , hook devices  114  are symmetrically and movably disposed at opposite sides of the receiving space  112 . The hook devices  114  are disposed at the rear side of the receiving space  112  to engage a plurality of protrusions  17  disposed on the right and left rear sides of the cassette body  10 .  
      The operation of the paper feeding cassette according to the embodiments of the present general inventive concept will now be explained with reference to FIGS.  1  to  6 . However, it should be understood that this description can also be applied to the embodiment of  FIG. 7 .  
      The plurality of sheets of recording medium P are stacked in the cassette body  10  to contact the plurality of contacting surfaces  11  formed at one inner side of the cassette body  10  to form the reference surface.  
      The cassette body  10  and the cover  30  are then inserted into the mount part  110  of the image forming apparatus  100 .  
      As the paper feeding cassette is inserted into the mount part  110 , the cover  30  is held by the receiving recess  111  to prevent the cover  30  from being inserted further into the receiving space  112  such that the cassette body  10  is slid with respect to the cover  30  to the rear side of the receiving space  112 .  
      As the cassette body  10  is inserted in the mount part  110  toward the rear side of the receiving space  112 , the protrusions  17  on the cassette body  10  move toward the hook devices  114  such that each protrusion  17  engages each hook device  114  and the cassette body  10  is fixedly mounted to the image forming apparatus  100 .  
      As described above, since the cassette body  10  and the cover  30  are slid relative to each other, the guide member  21  fixedly connected to the cover  30  is inserted into the guide recess  22   c  (see  FIGS. 3B and 4B ) of the biasing member  22  disposed at the inside of the cassette body  10 . Accordingly, the second end  22   b  of the biasing member  22  is elastically biased to press one side of the stacked sheets of recording media P so that widths of the sheets of recording medium P can be aligned against the reference surface.  
      In other words, according to the present embodiment, the stacked sheets of recording medium P can be automatically aligned simultaneously with a mounting of the paper feeding cassette to the image forming apparatus  100 .  
      Therefore, the alignment operation is very easily performed to provide convenience to users of the image forming apparatus  100 . Additionally, the sheets of recording medium P are accurately aligned so that the aligned sheets of recording medium P can be accurately and minutely supplied to an image forming part of the image forming apparatus  100 . Therefore, a printing quality can be enhanced.  
      If the paper feeding cassette has a structure in which the recording medium P are pressurized from only one side in the cassette body  10 , the pressurizing force for aligning the sheets of recording medium P is not too excessive so as to cause overlapped sheets of the recording medium P to be picked up by the pick up roller  55 .  
      According to the various embodiments of the present general inventive concept, sheets of recording medium can be more accurately picked up and a stable image quality can be obtained.  
      According to the various embodiments of the present general inventive concept, sheets of a recording medium can be easily and accurately aligned.  
      Additionally, according to the embodiments of the present general inventive concept, sheets of a recording medium are prevented from overlapping when being picked. Additionally, individual sheets are properly picked up from the paper feeding cassette.  
      Although a few embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the appended claims and their equivalents.