Image forming apparatus

Abstract

Disclosed is an image forming apparatus incorporating a discharging unit that discharges a printing medium outside the housing of the image forming apparatus, and which stacks the discharged printing medium. The discharging unit includes a discharging part arranged on the transportation path of the printing medium in the housing, a stacking lever rotatably supported on the housing and a driving unit that drives the stacking lever to rotate. The discharging part discharges a printing medium outside the housing, and stacks the discharged printing medium on a stacking unit provided outside the housing. The stacking lever guides the stacking of the printing medium in the stacking unit. A control unit may be provided to control the driving unit so as to vary the revolution position of the stacking lever based on the discharged position of the printing medium discharged by the discharging part.

1 . An image forming apparatus, comprising:
 a housing;   an image forming unit disposed in the housing, the image forming apparatus being configured to form an image on a printing medium; and   a discharging unit configured to discharge the printing medium outside the housing, and to stack a discharged printing medium, the discharging unit comprising:   a discharging part disposed on a printing medium transportation path in the housing, the discharging part being configured to discharge the printing medium outside the housing;   a stacking unit on which printing media discharged outside the housing are stacked;   a stacking lever which is rotatably disposed in the housing, the stacking lever being configured to guide stacking of the printing medium in the stacking unit;   a driving unit configured to rotate the stacking lever; and   a control unit configured to control the driving unit so as to vary a revolution position of the stacking lever based on a discharged position of the printing medium being discharged by the discharging part.   
     
     
         2 . The image forming apparatus according to  claim 1 , further comprising a discharging sensor disposed on the printing medium transportation path, the discharging sensor being configured to sense the discharging position of the printing medium,
 wherein the control unit is configured to control the driving unit based on a sensing result of the discharging sensor.   
     
     
         3 . The image forming apparatus according to  claim 2 , wherein the control unit controls the driving unit so that an end portion of the stacking lever maintains an ascending state when a leading end portion of the printing medium enters the stacking unit, and so that the end portion of the stacking lever descends when a trailing end portion of the printing medium enters the stacking, unit. 
     
     
         4 . The image forming apparatus according to  claim 1 , wherein the discharging part comprises:
 a discharging roller disposed on a first rotation shaft rotatably arranged on the printing medium transportation path, and   an idle roller formed on a second rotation shaft rotatably arranged on the printing medium transportation path, the second rotation shaft extending parallel to the first rotation shaft.   
     
     
         5 . The image forming apparatus according to  claim 1 , wherein the stacking lever comprises:
 a revolution shaft disposed in the housing, and   a lever member rotatable about the revolution shaft, the lever member comprising an operating unit ascending and descending by the driving unit and a pressing unit configured to come into a pressing contact with the printing medium.   
     
     
         6 . The image forming apparatus according to  claim 5 , wherein the pressing unit of the lever member is formed to have at least one of a rectilinear shape, a rounded shape having a rounded end, a step shape and a bent shape bent toward the stacking unit as it extends away from the revolution shaft toward end of the pressing unit. 
     
     
         7 . The image forming apparatus according to  claim 5 , wherein the stacking lever comprises:
 a second revolution shaft arranged in the housing,   a second lever member rotatably disposed on the second revolution shaft, the second lever member comprising a second operating unit interlocking with the operating unit of the lever member to ascend and descend therewith and a second pressing unit configured to come into a pressing contact with the printing medium in a pressing direction opposite to a direction in which the pressing unit of the lever member presses the printing medium, and   a link member which connects the operating unit of the lever member and the second operating unit of the second lever member.   
     
     
         8 . The image forming apparatus according to  claim 5 , wherein the stacking lever comprises:
 a second revolution shaft arranged in the housing,   a second lever member rotatably disposed on the second revolution shaft, the second lever member comprising a second pressing unit configured to come into a pressing contact with the printing medium in a pressing direction opposite to a direction in which the pressing unit of the lever member presses the printing medium, and   a weight coupled to the second lever member, the weight biasing the second pressing unit toward the pressing unit of the lever member by its own weight.   
     
     
         9 . The image forming apparatus according to  claim 1 , wherein the driving unit comprises a solenoid having an operating rod that ascends and descends by an electromagnetic force, the operating rod being connected to an end portion of the stacking lever. 
     
     
         10 . The image forming apparatus according to  claim 1 , wherein the driving unit comprises:
 a driving source configured to supply a rotation force,   a cam member driven by the driving source to rotate, the cam member being configured to regulate an ascending height of an end of the stacking lever based on a rotational position of the cam member, and   an elastic member elastically biasing the end of the stacking lever toward the earn member.   
     
     
         11 . The image forming apparatus according to  claim 1 , wherein the stacking lever comprises:
 a revolution shaft arranged in the housing, and   a plurality of lever members disposed to the revolution shaft spaced apart from one another by a predetermined interval, and respectively comprise an operating unit ascending and descending by the driving unit, and a pressing unit pressing on the printing medium, and   wherein the control unit controls the driving unit so that an end part of a lever member positioned in a central part of the printing medium in its widthwise direction among the plurality of lever members further descends in comparison to an end part of another lever member positioned at an edge part of the printing medium in the widthwise direction.   
     
     
         12 . The image forming apparatus according to  claim 11 , wherein the driving unit comprises:
 a driving source configured to supply a rotational force,   a plurality of cam members which are rotated by the rotational force supplied by the driving source, the plurality of cam members being configured to regulate an ascending height of the operating unit of each of the plurality of lever members based on a rotation position of the plurality of cam members, and   a plurality of elastic members which elastically bias the operating unit of each of the plurality of lever members toward the cam members.   
     
     
         13 . The image forming apparatus according to  claim 11 , wherein the driving unit comprises:
 a solenoid with an operating rod that ascends and descends by an electromagnetic force,   an ascending/descending member which is interlocked with ascending and descending of the operating rod to thereby ascend and descend, and   a plurality of elastic members provided between the ascending/descending member and the operating unit of each of the plurality of lever members to elastically bias the operating unit of each of the plurality of lever members.   
     
     
         14 . An image forming apparatus, comprising:
 a housing;   an image forming unit disposed in the housing, the image forming apparatus being configured to form an image on a printing medium; and   a discharging unit configured to discharge the printing medium outside the housing, and to stack discharged printing media, the discharging unit comprising:   an operating plate rotatably supported in the housing;   a driving unit disposed in the housing, the driving unit being configured to drive the operating plate to rotate;   a discharging part supported on the operating plate, the discharging part being configured to discharge the printing medium outside the housing;   a stacking unit in which the printing medium discharged outside the housing by the discharging part is stacked;   a stacking lever supported on the operating plate, the stacking lever being configured to guide stacking of the printing medium in the stacking unit based on a rotational position variation of the operating plate; and   a control unit which controls the driving unit to vary a revolution position of the stacking lever based on a discharged position of the printing medium being discharged by the discharging part.   
     
     
         15 . The image forming apparatus according to  claim 14 , further comprising a discharging sensor disposed on a transportation path of the printing medium, the discharging sensor being configured to sense the discharged position of the printing medium,
 wherein the control unit is configured to control the driving unit based on a sensing result of the discharging sensor.   
     
     
         16 . The image forming apparatus according to  claim 14 , wherein the control unit controls the driving unit so that an end portion of the stacking lever maintains an ascending state when a leading end portion of the printing medium enters the stacking unit, and so that the end portion of the stacking lever descends when a trailing end portion of the printing medium enters the stacking unit. 
     
     
         17 . The image forming apparatus according to  claim 14 , wherein the discharging part comprises:
 a discharging roller which formed on a first rotation shaft supported on the operating plate, and   an idle roller formed on a second rotation shaft supported on the operating plate, the second rotation shaft extending parallel to the first rotation shaft.   
     
     
         18 . The image forming apparatus according to  claim 17 , wherein the operating plate is configured to revolve about the first rotation shaft or about the second rotation shaft. 
     
     
         19 . The image forming apparatus according to  claim 14 , wherein the driving unit comprises a solenoid with an operating rod that ascends and descends by an electromagnetic force, the operating rod being connected to a side of the operating plate. 
     
     
         20 . The image forming apparatus according to  claim 14 , wherein the driving unit comprises:
 a driving source configured to supply a rotational force;   a cam member which is driven to rotate by the rotational force supplied by the driving source, the cam member being configured to regulate a revolution position of an end of the operating plate based on a rotation position of the cam member, and   an elastic member configured to elastically bias the end of the operating plate toward the cam member.