Patent Publication Number: US-7215906-B2

Title: Developing unit with gripper that covers developer filling opening

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a developing unit for developing an electrostatic latent image by adhering a developer on the electrostatic latent image, used in an image forming device such as a copying machine, a printer and a facsimile machine. 
   2. Description of Related Art 
   An image forming device carries out an image forming process by adhering a developer (toner) on an electrostatic latent image carrier on which an electrostatic latent image is formed. Accompanying the image forming process, the developer is consumed and a remaining amount of the developer decreases. Therefore, the developer is required to be replenished as needed. Accordingly, a developing unit is provided removably with respect to the image forming device so that when necessary, the developing unit can be removed from the image forming device to replenish the developer or to replace the developing unit. 
   In general, a gripper is provided on the developing unit so that the developing unit can be inserted and removed easily. Various conventional improvements on the gripper have been proposed. For example, according to one conventional improvement, an auxiliary tank of the toner also functions as the gripper. According to another conventional improvement, a concave part is formed on an upper part of an upper frame of a process cartridge in a longitudinal direction so that an operator&#39;s finger can be placed in. 
   When the developing unit is inserted removably in the image forming device as described above, the developer can be replenished in the developing unit and the developing unit can be reused. However, if developer that is noncompliant with the image forming device is replenished in the developing unit and the developing unit is reused, there are cases in which the developer causes a negative influence on the image forming device. Therefore, a countermeasure is required for preventing undesired developer from being replenished in the developing unit. 
   Accordingly, there is a demand for a developing unit which prevents the developer from being replenished easily in the developing unit by a simple structure using the gripper generally provided on the developing unit. 
   SUMMARY OF THE INVENTION 
   According to an aspect of the present invention, a developing unit includes a container, a developer replenish opening and a gripper. The container accumulates developer inside. The container includes a developer carrier which adheres the developer onto an electrostatic latent image carrier. The developer replenish opening is formed on the container. The gripper is fixed on an outer surface of the container so as to cover the developer replenish opening. It is preferable that a cover is provided on the container so as to seal the developer replenish opening, and the gripper is fixed by being provided so as to cross the cover. The gripper is preferable to be fixed on the container by screws at both sides of the cover. Furthermore, the gripper is preferable to be fixed on the container by welding at both sides of the cover. 
   According to the aspect of the present invention, the gripper is fixed on the container so as to cover the developer replenish opening from where the developer is replenished. Therefore, unless removing the gripper from the container, the developer cannot be replenished from the developer replenish opening. If the gripper is removed from the container, the developing unit without the gripper becomes extremely troublesome to be inserted and removed. Therefore, a certain deterrent effect can be expected for the removable of the gripper. As a result, the developer may not be replenished easily in the developing unit. In addition, since the gripper which is provided conventionally is used, a new component is not necessary to be added. 
   Furthermore, the gripper is fixed by being provided so as to cross the cover sealing the toner replenish opening. Therefore, the cover can be prevented from being removed from the developer replenish opening by a simple structure. Moreover, the gripper is fixed on the container by the screws at both sides of the cover. As a result, the developing unit can be disassembled easily when recycling. The gripper is fixed on the container by welding at both sides of the cover. As a result, the gripper becomes extremely difficult to be removed and safety can be improved even more. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       FIG. 1  is a perspective view showing a developing unit according to an embodiment of the present invention. 
       FIG. 2  is a perspective view of a gripper viewed from an upper side. 
       FIG. 3  is a perspective view of the gripper viewed from a lower side. 
       FIG. 4  is a perspective view showing a state in which the gripper is removed. 
       FIG. 5  is a cross-sectional view of a toner filling opening under a state in which the gripper is set. 
       FIG. 6  is a cross-sectional view of an attaching protrusion under the state in which the gripper is set. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Embodiments of the present invention will be described. Further, the embodiments to be described below are preferable specific examples for implementing the present invention. Therefore, there are various technical limitations in the description. However, unless explicitly stated in the following description to limit the present invention, the present invention shall not be limited to the embodiments. 
     FIG. 1  is a perspective view of a developing unit  1  viewed from an upper side. The developing unit  1  includes a container  2  and an upper cover  3 . Inside the container  2 , a replenish chamber is formed for accumulating a toner which is a developer. A developing roller  4  is mounted rotatably on an end part of the developing unit  1  at a right side of the page of  FIG. 1 . An agitator is provided in the replenish chamber. By the agitator being rotated, the agitator agitates the toner and replenishes the toner on the developing roller  4 . This structure is the same as the structure of a conventional developing unit. The upper cover  3  is fixed so as to seal an upper opening of the container  2 . The upper cover  3  and the container  2  are sealed with an adhesive. Accordingly, the toner is prevented from leaking. In addition, it becomes extremely difficult to remove the upper cover  3  and to replenish the toner. 
   At a front side of the page of  FIG. 1 , a gripper  5  is fixed on the container  2  of the developing unit  1 . The gripper  5  includes a handle  6  and a fixed part  7 . The handle  6  is formed so as to protrude outward from the fixed part  7 .  FIG. 2  is a perspective view of the gripper  5  viewed from an upper side.  FIG. 3  is a perspective view of the gripper  5  viewed from a lower side. 
   The handle  6  includes an upper surface member  8  and a side surface member  9 . The upper surface member  8  is plate shaped and rectangular. One end part of the upper surface member  8  is formed integrally on the fixed part  7 . The side surface member  9  is suspended from a periphery of the upper surface member  8 . The side surface member  9  has a prescribed width and is formed in the shape of the letter U. A belt-shaped member  10  is provided between the side surface member  9  and the fixed part  7 . The belt-shaped member  10  is suspended from a lower surface of the upper surface member  8 . The belt-shaped member  10  is provided with a prescribed interval spaced from the side surface member  9 . The belt-shaped member  10  is formed in the shape of the letter U. A plurality of rectangular ribs  11  are provided between the side surface member  9  and the belt-shaped member  10 . Each of the ribs  11  is formed to be orthogonal to the upper surface member  8 , the side surface member  9  and the belt-shaped member  10 . The handle  6  can be gripped easily by inserting an operator&#39;s finger into the space between the belt-shaped member  10  and the fixed part  7 . Since the plurality of ribs  11  are provided, the gripper  6  is strong enough for a gripping force. 
   The fixed part  7  includes a rectangular front surface member  12  and a peripheral surface member  13 . The front surface member  12  is formed integrally with the handle  6 . The peripheral surface member  13  having a prescribed width is provided to surround the front surface member  12 . A pair of oval-shaped attaching concaves  14   a  and  14   b  are formed on both sides of the handle  6  on the front surface member  12 . Each of the attaching concaves  14   a  and  14   b  is caved in toward the container  2 . Screw mounting holes  15   a  and  15   b  and boss mounting holes  16   a  and  16   b  are formed through the attaching concaves  14   a  and  14   b , respectively. As shown in  FIG. 2 , on the left-side attaching concave  14   a , the boss mounting hole  16   a  is formed below the screw mounting hole  15   a . On the right-side attaching concave  14   b , the boss mounting hole  16   b  is formed below the screw mounting hole  15   b . A plurality of ribs  17   a  through  17   e  are formed inside the peripheral surface member  13 . Each of the ribs  17   a  through  17   e  is orthogonal to the longitudinal direction of the fixed part  7 , respectively. The ribs  17   a  and  17   e  are formed in proximity of a side of the attaching concaves  14   a  and  14   b , respectively. The ribs  17   a  and  17   e  improve the strength of the attaching concaves  14   a  and  14   b . As to be described later, the ribs  17   a  and  17   e  are used for positioning when fitting attaching protrusions  20   a  and  20   b . The ribs  17   b  through  17   d  are also formed with a prescribed interval between one another to strengthen the fixed part  7 . 
     FIG. 4  is a perspective view of the developing unit  1  under a state in which the gripper  5  is removed. A circular toner filling opening  18  is formed on a side surface of the container  2 . A cylindrical shaped part is formed at the toner filling opening  18 , protruding a prescribed length from the side surface of the container  2 . An opening of the toner filing opening  18  is sealed by a cap  19 . 
   A pair of the attaching protrusions  20   a  and  20   b  are fixed on the container  2  at both the left and right of the toner filling opening  18 . The left-side attaching protrusion  20   a  is provided in proximity to the toner filing opening  18 . The right-side attaching protrusion  20   b  is provided at a position located away from the toner filling opening  18 . The pair of the attaching concaves  14   a  and  14   b  formed on the fixed part  7  of the gripper  5  are fit onto the attaching protrusions  20   a  and  20   b , respectively. The attaching protrusions  20   a  and  20   b  are formed in a rectangular shape. The shape of the attaching protrusions  20   a  and  20   b  is approximately the same as the peripheral surface member  13  of the fixed part  7  and the ribs  17   a  and  17   e  formed to surround the attaching concaves  14   a  and  14   b . Therefore, by fitting the pair of the attaching concaves  14   a  and  14   b  onto the attaching protrusions  20   a  and  20   b , the gripper  5  is positioned on the container  2 . 
   When the gripper  5  is set on the container  2 , the toner filling opening  18  is fit in the space between the ribs  17   d  and  17   e  of the fixed part  7 .  FIG. 5  is a vertical cross-sectional view of the toner filling opening  18  under a state in which the gripper  5  is set. By setting the gripper  5 , the toner filling opening  18  is covered by the gripper  5 . Accordingly, unless removing the gripper  5 , the toner filling opening  18  cannot be opened from the outside. An attaching frame  23  is provided at the right side of the toner filing opening  18 . When the gripper  5  is set, the attaching frame  23  is fit between the ribs  17   c  and  17   d  of the fixed part  7 . As a result, an attached strength of the gripper  5  increases. 
   A screw hole  21   a  and a boss  22   a  are provided on the attaching protrusion  20   a . A screw hole  21   b  and a boss  22   b  are provided on the attaching protrusion  20   b . When the attaching concave  14   a  is fit onto the attaching protrusion  20   a , the screw mounting hole  15   a  and the boss mounting hole  16   a  formed on the attaching concave  14   a  are disposed at a position approximately consistent with the screw hole  21   a  and the boss  22   a , respectively. In the same manner, the screw mounting hole  15   b  and the boss mounting hole  16   b  formed on the attaching concave  14   b  are disposed at a position approximately consistent with the screw hole  21   b  and the boss  22   b , respectively.  FIG. 6  is a vertical cross-sectional view of the attaching protrusion  20   a  under a state in which the gripper  5  is set. A screw  24  is inserted through the screw mounting hole  15   a  and the screw hole  21   a  and fixed. The boss  22   a  is inserted though the boss mounting hole  16   a . A positioning is carried out by inserting the boss  22   a  through the boss mounting hole  16   a . The screw mounting hole  15   a  and the screw hole  21   a  are positioned accurately. The attaching concave  14   b  and the attaching protrusion  20   b  are positioned in the same manner. By heating a summit of the bosses  22   a  and  22   b , the bosses  22   a  and  22   b  can be welded onto the attaching concaves  14   a  and  14   b . Accordingly, the fixed part  7  is fixed onto the container  2  and the gripper  5  becomes difficult to be removed. 
   As described above, by fixing the gripper  5  onto the container  2 , the toner filling opening  18  is covered by the gripper  5 . By fixing with the screw  24  and by welding the bosses  22   a  and  22   b , the gripper  5  becomes extremely difficult to be removed. To facilitate recycling, the bosses  22   a  and  22   b  may be not welded. Accordingly, by removing the screw  24 , the gripper  5  can be separated from the container  2  without destroying the gripper  5 .