Patent Publication Number: US-8526860-B2

Title: Developing unit and image forming apparatus having the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. §119(a) from Korean Patent Application No. 2009-0088543, filed on Sep. 18, 2009 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
     BACKGROUND 
     1. Field of the Invention 
     Embodiments of the present general inventive concept relate to a developing unit to deliver developer in a predetermined direction and an image forming apparatus having the same. 
     2. Description of the Related Art 
     Generally, image forming apparatuses are devised to form an image on a printing medium according to inputted image signals. Examples of image forming apparatuses include printers, copiers, facsimiles, and so-called multi-functional devices that combine some of the functionalities of the aforementioned devices. 
     In operation of an image forming apparatus, light is irradiated to a photosensitive body that has been charged with a predetermined electric potential, so as to form an electrostatic latent image on a surface of the photosensitive body. As toner as developer is supplied to the electrostatic latent image, a visible toner image is formed. The toner image formed on the photosensitive body is directly transferred to a printing medium or is indirectly transferred to the printing medium by way of an intermediate transfer body. The transferred image is fused to the printing medium via a fusing process. 
     The above-described printing process may need delivery of the developer. Conventionally, delivery of the developer is accomplished by an agitator or an auger. 
     However, the agitator or the auger is designed to deliver the developer in a direction perpendicular to a rotating axis thereof, having a limit in a delivery direction of the developer. 
     SUMMARY 
     Therefore, it is a feature and utility an aspect of the present general inventive concept to provide a developing unit to deliver developer in a predetermined direction and an image forming apparatus having the same. 
     Additional features and utilities 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 exemplary embodiments of the present general inventive concept. 
     Embodiments of the present general inventive concept provide a developing unit to deliver developer in various directions or in a predetermined direction and an image forming apparatus having the same. 
     Embodiments of the present general inventive concept may include a developing unit detachably mounted in an image forming apparatus and may include a developing roller and a supply roller to supply developer to a photosensitive body, the developing unit may further include a developer housing to store the developer, and a delivery unit to deliver the developer by being rotated in the developer housing, the delivery unit may include a rotating shaft, and a delivery member coupled to the rotating shaft and arranged to come into contact with the developer via rotation thereof, the delivery member may include at least one delivery element arranged in an axial direction of the rotating shaft, and the developer housing including at least one protrusion arranged to interfere with the at least one delivery element during rotation of the delivery unit. 
     The at least one protrusion may be arranged at a position close to any one side of the at least one delivery element on the basis of the center of the at least one delivery element, so as to cause bending of a side portion of the at least one delivery element. 
     The at least one protrusion may be arranged close to a left side of a surface of the at least one delivery element so as to come into contact with the at least one delivery element when the surface of the at least one delivery element is intended to face a direction deflected leftward from a rotation tangential direction of the delivery unit. 
     The at least one protrusion may be arranged close to a right side of a surface of the at least one delivery element so as to come into contact with the at least one delivery element when the surface of the at least one delivery element is intended to face a direction deflected rightward from a rotation tangential direction of the delivery unit. 
     The at least one delivery element may be formed by dividing the delivery member into a plurality of delivery elements, and the at least one protrusion may be arranged to correspond to the surface of the at least one delivery element. 
     The at least one protrusion may include a plurality of protrusions arranged in a line in an axial direction of the rotating shaft of the delivery unit. 
     The at least one protrusion may include a plurality of protrusions arranged in zigzags in an axial direction of the rotating shaft of the delivery unit. 
     The delivery member may include an elastic thin film member. 
     An angle between the surface of the at least one delivery element and the direction deflected from the rotation tangential direction of the delivery unit may be an acute angle. 
     Embodiments of the present general inventive concept may include an image forming apparatus having a developer delivery system, the developer delivery system may include a developer housing to store the developer, and a delivery unit to deliver the developer by being rotated in the developer housing, the delivery unit may include a rotating shaft, and a delivery member coupled to the rotating shaft and adapted to provide the developer with delivery force via rotation thereof, the delivery member may include at least one delivery element arranged in an axial direction of the rotating shaft, and the developer housing may include a direction change element to change a direction of the developer delivery force by causing the at least delivery element to be bent in a predetermined direction during rotation of the delivery unit. 
     The direction change element may include at least one protrusion formed in the developer housing. 
     The at least one protrusion may be arranged within a rotation radius of the at least one delivery element, so as to come into contact with the at least one delivery element. 
     The at least one protrusion may be arranged at a position to apply deformation force to the at least one delivery element, so as to allow an orientation direction of a surface of the at least one delivery element to be changed from a first direction as a rotation tangential direction of the delivery unit to a second direction as a predetermined delivery force application direction. 
     Embodiments of the present general inventive concept may include a developer delivery system that may include a developer housing to store developer, and a delivery unit to deliver the developer by being rotated in the developer housing, the delivery unit may include a rotating shaft, and a film member coupled to the rotating shaft and adapted to push and deliver the developer in a predetermined direction, the film member may include at least one delivery element arranged in an axial direction of the rotating shaft, and the developer housing may include at least one interference member formed in the developer housing and adapted to interfere with the at least one delivery element during rotation of the delivery unit so as to change a developer push direction. 
     Embodiments of the present general inventive concept may include a waste developer return unit that may include a waste developer housing into which waste developer is introduced, and a delivery unit to deliver the waste developer by being rotated in the waste developer housing, the delivery unit may include a rotating shaft, and a delivery member coupled to the rotating shaft and adapted to push and deliver the developer in a predetermined direction via rotation thereof, the delivery member may include at least one delivery element arranged in an axial direction of the rotating shaft, and the waste developer housing may include at least one protrusion protruding from an inner surface of the waste developer housing and adapted to come into contact with the at least one delivery element so as to change an orientation direction of a surface of the at least one delivery element. 
     Embodiments of the present general inventive concept further include a developing unit within an image forming apparatus including a developer housing to store a developer, and a delivery unit to rotatably deliver the developer along a developer delivery direction, wherein the delivery unit further includes a rotating shaft and flexible driving member attached thereto to direct the developer along the developer delivery direction, and the developer housing further includes a plurality of protrusions along an inner surface thereof to provide multiple developer delivery directions of the developer within the developer housing at separate time intervals. 
     Embodiments of the present general inventive concept further include a method of modifying developer delivery direction within a developer unit of an image forming apparatus including rotating a delivery unit with an elongated delivery member within a developer housing of the developer unit; and colliding the delivery member with at least one protrusion positioned on an inner surface of the developer housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other features and utilities of the present general inventive concept will become apparent and more readily appreciated from the following description of the exemplary embodiments, taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a view illustrating an interior configuration of an image forming apparatus according to an exemplary embodiment of the present general inventive concept; 
         FIG. 2  is a perspective view illustrating an exterior appearance of a developing unit; 
         FIG. 3  is a sectional view of the developing unit; 
         FIG. 4  is a perspective view illustrating an interior configuration of a developer housing; 
         FIG. 5  is a detailed view illustrating the interior of the developer housing; 
         FIG. 6  is a detailed view illustrating a developer delivery system; 
         FIGS. 7A and 7B  are views illustrating a mutual operational relationship of a delivery element and a protrusion; 
         FIGS. 8A to 8C  are conceptual views illustrating a developer delivery direction based on positional relationship of the delivery element and the protrusion; 
         FIG. 9  is a view illustrating a developer delivery system according to an exemplary embodiment of the present general inventive concept; and 
         FIG. 10  is a view illustrating a developer delivery system according to an exemplary embodiment of the present general inventive concept. 
         FIGS. 11A-11C  are detailed views illustrating various positions of the protrusions within the developer housing. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     Reference will now be made in detail to the exemplary embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The exemplary embodiments are described below in order to explain the present general inventive concept by referring to the figures. 
       FIG. 1  is a view illustrating an interior configuration of an image forming apparatus according to an exemplary embodiment of the present general inventive concept.  FIG. 2  is a perspective view illustrating an exterior appearance of a developing unit.  FIG. 3  is a sectional view of the developing unit. 
     As illustrated in  FIG. 1 , the image forming apparatus  1  may include a body  10  defining an exterior appearance of the image forming apparatus  1 , a supply unit  20  to supply paper P stored therein, a developing unit  30  to form a developer image on the paper P supplied via the supply unit  20 , a Light Scanning Unit (LSU)  40  to form an electrostatic latent image on a photosensitive body  31  of the developing unit  30 , a fusing unit  50  to fuse developer transferred to the paper P, a paper discharge unit  60  to discharge the paper P, on which the image has been completely formed, out of the body  10 , and a double-sided printing unit  70  to return the paper P, on a surface of which the image has been completely formed, to the developing unit  30 . 
     The supply unit  20  may serve to supply the paper P to the developing unit  30 , and may include a paper cassette  21  separably mounted to the body  10 , a knock-up plate  22  installed in the paper cassette  21  to load the paper P thereon, and a pickup roller  24  to pick up the paper S on the knock-up plate sheet by sheet so as to transmit the paper P to the developing unit  30 . Feed rollers  11  may be installed in the body  10  to deliver the paper P picked up by the pickup roller  24  to the developing unit  30 . 
     The light scanning unit  40  may irradiate light containing image information to the photosensitive body  31 , so as to form an electrostatic latent image on the photosensitive body  31 . 
     The fusing unit  50  may serve to fuse the developer image formed on the paper P by applying heat and pressure to the paper P. The fusing unit  50  may include a heating roller  52  having a heater  51 , and a press roller  53  to press the paper P using the heating roller  52 . As the paper P receives heat and pressure while passing through a gap between the heating roller  52  and the press roller  53 , the developer image on the paper P may be fused to the paper P. 
     The paper discharge unit  60  may include a paper discharge roller  62  and serve to discharge the paper P, having passed through the fusing unit  50 , out of the body  10 . 
     The double-sided printing unit  70  may serve to return the paper P, on a surface of which the image has been completely formed, to the developing unit  30 , so as to enable printing of both surfaces of the paper P. The double-sided printing unit  70  may include a double-sided printing guide  71  to define a return path of the printed paper P, and a series of return rollers  72  installed on the return path of the printed paper P to deliver the paper P. 
     The developing unit  30  may form the developer image on the paper P delivered from the paper supply unit  20 . The developing unit  30 , as illustrated in  FIGS. 2 and 3 , may include the photosensitive body  31  on the surface of which the electrostatic latent image is formed by the light scanning unit  40 , a charging roller  32  to charge the photosensitive body  31 , a developing roller  33  to develop the electrostatic latent image formed on the photosensitive body  31  into a developer image by supplying the developer to the photosensitive body  31 , a supply roller  34  to supply the developer to the developing roller  33 , a cleaning roller  35  to clean the charging roller  32 , and a housing  36  defining an exterior appearance of the developing unit  30 . A transfer roller  12  may be installed in the body  10  to transfer the developer image of the photosensitive body  31  to the paper P by pressing the paper P toward the photosensitive body  31 . 
     A developer housing  37  to store the developer may be arranged in the developing unit  30 . The developer housing  37  may serve to store the developer therein at normal times, and to supply the developer to the supply roller  34  during a printing operation. 
     The developer housing  37  may include a first developer housing  38  in which a developer delivery system  100  according to the exemplary embodiment of the present general inventive concept is provided, and a second developer housing  39  to store the developer delivered from the first developer housing  38 . 
     Hereinafter, the developer delivery system  100  will be described in detail. 
       FIG. 4  is a perspective view illustrating an interior configuration of the developer housing,  FIG. 5  is a detailed view illustrating the interior of the developer housing,  FIG. 6  is a detailed view of the developer delivery system,  FIGS. 7A and 7B  are views illustrating the mutual operational relationship of a delivery element and a protrusion, and  FIGS. 8A to 8C  are conceptual views illustrating a developer delivery direction based on positional relationship of the delivery element and the protrusion. 
     As illustrated in  FIGS. 4 to 6 , the developer delivery system  100  may be provided in the first developer housing  38 . The developer delivery system  100  may include the first developer housing  38  to store the developer, and a delivery unit  110  to deliver the developer while being rotated in the first developer housing  38 . The width of the first developer housing is represented by  38 W in  FIG. 5  and the length of the first developer housing  38  is represented by  38 L in  FIG. 4 . 
     The delivery unit  110  may include a rotating shaft  113  defining a rotatable body of the delivery unit  110 , and a delivery member  115  rotatably coupled to the rotating shaft  113  and arranged to interfere with the developer via rotation thereof. The height of the delivery member  115  is represented by  115 H in  FIG. 6  and the height of the rotating shaft  113  is represented by  113 H in  FIG. 6   
     The rotating shaft  113  and the delivery member  115  may be arranged in a longitudinal direction of the developing unit  30 . The delivery member  115  is an elastic thin film member. 
     The delivery member  115  may include at least one delivery element  115   a  arranged in an axial direction of the rotating shaft  113  with a height of  115   a H, as illustrated in  FIG. 6 . The delivery element  115   a  may be formed by dividing the delivery member  115  into a plurality of independently movable elements. The space in a longitudinal direction between delivery member  115  and delivery element  115   a  is represented by  160  in  FIGS. 7A ,  7 B, and  8 A- 8 C. A space  180 , illustrated in  FIG. 8A , may exist between the delivery element  115   a  and an inner surface of the first developer housing  38 . 
     Specifically, although a part of the delivery member  115  is integrally coupled to the rotating shaft  113 , the remaining part of the delivery member  115  used to directly apply delivery force to the developer is divided to form the at least one independently movable delivery element  115   a.    
     The first developer housing  38  may include at least one protrusion  130  protruding from an inner surface of the first developer housing  38  and configured to come into contact with the at least one delivery element  115   a  during rotation of the delivery unit  110 . The protrusion  130  may be located within a rotation radius of the delivery element  115   a.    
     As illustrated in  FIGS. 7A and 7B , when the at least one protrusion  130  comes into direct contact with the at least one delivery element  115   a , the protrusion  130  may act to change a developer delivery direction. 
     After the delivery unit  110  begins to be rotated and before the delivery element  115   a  comes into contact with the protrusion  130 , a developer delivery force direction may be applied in a first direction A as a rotation tangential direction of the rotating shaft  113  of the delivery unit  110 . In this case, a surface of the delivery element  115   a  faces the first direction A as the rotation tangential direction of the rotating shaft  113 . 
     Then, when the delivery element  115   a  comes into contact with and interferes with the protrusion  130  arranged close to the left side of the surface of the delivery element  115   a  via further rotation of the delivery unit  110 , the delivery element  115   a  may elastically deform so that a left portion of the surface of the delivery element  115   a  is bent, causing the surface of the delivery element  115   a  to face a second direction B that is deflected leftward from the first direction A. The second direction B is a direction along which a user may intend to apply a developer delivery force. In addition, an angle between the first direction A and the second direction B may be an acute angle θ. 
     Although  FIGS. 7A and 7B  illustrate an example wherein the protrusion  130  is arranged close to the left side of the surface of the delivery element  115   a , on the contrary, the protrusion  130  may be arranged close to the right side of the surface of the delivery element  115   a  as illustrated in  FIG. 8A . In this case, a right portion of the main surface of the delivery element  115   a  is bent, causing the main surface of the delivery element  115   a  to face a rightward deflected direction C. 
     As illustrated in  FIG. 8B , one or more protrusions  130  may be aligned in a line in the axial direction of the rotating shaft  113  of the delivery unit  110 . In this case, the main surface of the delivery element  115   a  faces the leftward deflected direction B and thus, developer delivery force acts in the leftward deflected direction B throughout the axial direction of the rotating shaft  113 . Also, illustrated in  FIGS. 8B and 8C  is the height  130 H of the protrusions  130  and the width  130 W of the protrusions  130 . Although the protrusions  130  illustrated in the figures have a diameter as a width, the protrusions may comprise of other shapes, such as rectangles. 
     As illustrated in  FIG. 8C , one or more protrusions  130 ′ and  130 ″ may be arranged in zigzags in the axial direction of the rotating shaft  113  of the delivery unit  110 . In this case, the developer delivery direction may be changed with a time interval. The protrusion  130 ′ at a rear surface of the delivery member  115  may first interfere with a delivery element  115   a ′, temporarily changing the developer delivery direction (from a direction A′ to a direction B′). Subsequently, the protrusion  130 ″ at a front surface of the delivery member  115  may interfere with a delivery element  115   a ″, changing the developer delivery direction (from a direction A″ to a direction B″). 
     Considering the above principle described with reference to  FIGS. 7A to 7C  in conjunction with the delivery direction illustrated in  FIGS. 4 to 6  according to the exemplary embodiment of the present general inventive concept, the developer may move between the first developer housing  38  and the second developer housing  39  through a front space  37   a  and a rear space  37   b  of the developer housing  37 . The developer may be delivered in a direction “X” through the front space  37   a  and delivered in a direction “Y” through the rear space  37   b.    
     The width of the second developer housing  39  is represented by  39 W in  FIG. 5  and the length of the second developer housing  39  is represented by  39 L in  FIG. 4 . A height of the first developer housing  38  is represented by  38 H in  FIG. 5 , and a height of the second developer housing  39  is represented by  39 H in  FIG. 5 . 
     Now, the delivery of the developer through the rear space  37   b  will be described in more detail with reference to  FIG. 6 . Assuming that the delivery unit  110  may be rotated clockwise, the developer delivery force direction may be changed from the rotation tangential direction of the delivery unit  110  to the direction “Y” via mutual interference between the at least one protrusion  130  and the delivery element  115   a . Accordingly, the developer in the first developer housing  38  may be delivered to the second developer housing  39  through the rear space  37   b . As a delivery auger  39   a  delivers the developer within the second developer housing  39 , consequently, the developer may be supplied to the supply roller  34 , the developing roller  33 , and the photosensitive body  31 . 
     Hereinafter, an exemplary embodiment of the present general inventive concept will be described with reference to the accompanying drawing. 
       FIG. 9  is a view illustrating a developer delivery system according to an exemplary embodiment of the present general inventive concept. 
     A developer delivery system  200  according to the present exemplary embodiment may include a developer housing  250  having a bottom outlet hole  255 , and a delivery unit  210  to deliver the developer. 
     The delivery unit  210  may include a rotating shaft  213 , and a delivery member  215  rotatably coupled to the rotating shaft  213  and arranged to come into contact with the developer via rotation thereof. The delivery member  215  may be divided into a plurality of delivery elements  215   a ,  215   a ′, and  215   a ″ arranged in an axial direction. 
     The developer housing  250  may include protrusions  230  and  230 ′ arranged to interfere with the delivery elements  215   a  and  215   a ″ arranged at axially opposite sides of the rotating shaft  213  of the delivery unit  210 . 
     The delivery element  215   a  at the left side of the delivery unit  210  may interfere with the protrusion  230  arranged close to the right side of a surface of the delivery element  215   a . The delivery element  215   a ″ at the right side of the delivery unit  210  may interfere with the protrusion  230 ′ arranged close to the left side of a surface of the delivery element  215   a ″. The delivery element  215   a ′ at the center of the delivery unit  210  may rotate without interference with the protrusions  230  and  230 ′. 
     Accordingly, the delivery element  215   a  at the left side of the delivery unit  210  may cause a rightward developer delivery force, and the delivery element  215   a ″ at the right side of the delivery unit  210  may cause a leftward developer delivery force. The delivery element  215   a ″ at the center of the delivery unit  210  may cause forward developer delivery force. 
     Thereby, the developer in the developer housing  250  may be delivered through the outlet hole  255 . 
     The developer delivery system  200  according to the exemplary embodiment of  FIG. 9  may be directly applied to the second developer housing  39  of  FIGS. 1 to 6 . 
     Hereinafter, a further exemplary embodiment of the present general inventive concept will be described with reference to the accompanying drawing. 
       FIG. 10  is a view illustrating a developer delivery system according to a further exemplary embodiment of the present general inventive concept. 
     A waste developer delivery system  300  may include a delivery unit  310  to deliver waste developer and a waste developer housing  350  to store the waste developer. 
     The waste developer housing  350  according to the exemplary embodiment of  FIG. 10  generally has a bar shape, and may include a waste developer inlet hole  355  formed in one end thereof. Once waste developer is introduced through the waste developer inlet hole  355 , the waste developer may be delivered in a longitudinal direction, thereby being delivered to a space S defined in the other end of the waste developer housing  350 . 
     The delivery unit  310  may include a rotating shaft  313 , an auger  317  coupled to a part of the rotating shaft  313 , and a delivery member  318  coupled to the remaining part of the rotating shaft  313 . 
     The auger  317  may serve to deliver the waste developer introduced through the waste developer inlet hole  355  to the space S. The delivery member  318  may be divided into a plurality of delivery elements  318   a.    
     The waste developer housing  350  may include a plurality of protrusions  330  arranged close to the left side of a surface of each delivery element  318   a , respectively. 
     The waste developer introduced through the waste developer inlet hole  355  may reach an entrance of the space S via operation of the auger  317 . As the delivery member  318  is rotated clockwise, a developer delivery force direction may be changed leftward from a rotation tangential direction of the delivery unit  310  via interference between the respective delivery elements  318   a  and the protrusions  330 . 
     In this manner, the waste developer may be uniformly delivered throughout the empty space S. 
     With the use of the developer delivery system and the waste developer delivery system as described above, the developer and the waste developer may be delivered even to a space that conventionally has difficulty in delivery. 
       FIGS. 11A through 11C  further define the placement of the protrusions  130  within the first developer housing  38 . In particular,  FIG. 11A  illustrates the protrusions  130  in alignment with each other as well as aligned with the rotational axis of the delivery member  115 . Each protrusion  130  is in contact with the delivery elements  115 A on the delivery member  115 , but each delivery element  115 A is not yet bent. 
       FIG. 11B  illustrates the protrusions  130  separated from one another in equal distances in the rotational direction of the delivery member  115 . In particular, each protrusion  130  is separated from the next closest protrusion  130  by a distance of AA. The protrusions  130  are spaced apart from each other in a lengthwise direction by a distance XX. Further,  FIG. 11B  also illustrates a protrusion  130  contacting the delivery element  115   a , wherein the delivery element  115   a  is fully extended at an angle β. 
       FIG. 11C  illustrates the protrusions separated from one another in non-equal distances in the rotational direction of the delivery member  115 . In particular, two protrusions are distanced from each other by a distance of AA while another distance BB represents a distance between two other protrusions. The distance between protrusions  130  both in the rotational direction of the delivery member  115  and the lengthwise direction of the delivery member  115 , as illustrated with the arrow in  FIG. 11C , may vary. For example,  FIG. 11C  illustrates that the distance distances XX and YY in the lengthwise direction between protrusions  130  are not equal. Also illustrated in  FIG. 11C  is the delivery element  115   a  fully extended at angle β as well as not 
     As is apparent from the above description, in a developing unit and an image forming apparatus having the same according to the exemplary embodiment of the present general inventive concept, a delivery member to deliver developer may be deformed when coming into contact with a protrusion of a developer housing, enabling delivery of the developer in a predetermined direction. 
     Furthermore, the developer may be delivered in various directions or a predetermined direction. 
     Although a few exemplary embodiments of the present general inventive concept have been illustrated and described, it would be appreciated by those skilled in the art that changes may be made in these exemplary embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the claims and their equivalents.