Medium guiding device, image forming device, image reading device and post-processing device

Abstract

A medium guiding device includes an upstream side rollers pair, a downstream side rollers pair, a first rib, a second rib and an interlocking part. In a first conveying state where the medium is conveyed while being held by the upstream side rollers pair and separated from the downstream side rollers pair, the interlocking part retreats the first rib from a curved path and protrudes the second rib into the curved path. In a second conveying state where the medium is conveyed while being held by the downstream side rollers pair, the interlocking part protrudes the first rib into the curved path and retreats the second rib from the curved path.

1 . A medium guiding device comprising:
 an upstream side rollers pair which is provided on an upstream side in a conveyance direction of the medium from an apex of a curved path included in a medium conveyance path, and rotates while holding the medium to convey the medium;   a downstream side rollers pair which is provided on a downstream side in the conveyance direction from the apex in the medium conveyance path, and rotates while holding the medium to convey the medium;   a first rib which is provided on the downstream side in the conveyance direction from the upstream side rollers pair and on the upstream side in the conveyance direction from the apex, is configured to be protruded into and retreated from the curved path from an outside in a radial direction of the curved path, and comes into contact with the medium in a protruding state into the curved path; and   a second rib which is provided on the upstream side in the conveyance direction from the downstream side rollers pair and on the downstream side in the conveyance direction from the apex, is configured to be protruded into and retreated from the curved path from an inside in the radial direction of the curved path, and comes into contact with the medium in a protruding state into the curved path; and   an interlocking part which interlocks the first lib and the second rib so as to protrude and retreat them into and from the curved path, wherein
 in a first conveying state where the medium is conveyed while being held by the upstream side rollers pair and separated from the downstream side rollers pair, the interlocking part retreats the first rib from the curved path and protrudes the second rib into the curved path, and 
 in a second conveying state where the medium is conveyed while being held by the downstream side rollers pair, the interlocking part protrudes the first rib into the curved path and retreats the second rib from the curved path. 
   
     
     
         2 . The medium guiding device according to  claim 1 , wherein,
 the second rib is retreated from the curved path by the medium conveyed while being held between the upstream side rollers pair and the downstream side rollers pair, and   the interlocking part protrudes the first rib into the curved path interlocking with retreating of the second rib from the curved path.   
     
     
         3 . The medium guiding device according to  claim 1 , wherein, 
 the first rib and the second rib are elastically protruded into and retreated from the curved path.   
     
     
         4 . The medium guiding device according to  claim 1 , wherein,
 the interlocking part includes: 
 a first link part attached to the first rib and provided turnably around a first axis; 
 a second link part attached to the second rib, provided turnably around a second axis, and coupled to the first link part turnably and slidably; and 
 a biasing member biasing the first rib or the second rib directly or indirectly, wherein 
 in the first conveying state, a biasing force of the biasing member causes the first link part and the second link part to be turned such that the first rib is retreated from the curved path and the second rib is protruded into the curved path, and 
 in the second conveying state, the second rib is pressed by the conveyed medium and retreated from the curved path against the biasing force of the biasing member while tuning the second link part, and the first link part is turned while sliding relative to the second link part so as to protrude the first rib into the curved path. 
 
   
     
     
         5 . The medium guiding device according to  claim 1 , wherein,
 the interlocking part includes: 
 a driving part which causes the first rib to protrude into and retreat from the curved path; 
 a detecting part which detects the second rib retreated from the curved path; and 
 a biasing member which biases the second rib so as to protrude into the curved path, wherein 
 in the first conveying state, the driving part retreats the first rib from the curved path, and the second rib is biased by the biasing member to be protruded into the curved path, and 
 in the second conveying state, the second rib is pressed by the conveyed medium and retreated from the curved path against the biasing force of the biasing member, and based on a fact that the detecting part detects the retreated second rib, the driving part protrudes the first rib into the curved path. 
 
   
     
     
         6 . The medium guiding device according to  claim 1 , whereinthe interlocking part includes: 
 a first driving part which causes the first rib to protrude into and retreat from the curved path;   a second driving part which causes the second rib to protrude into and retreat from the curved path; and   a detecting part which detects that the downstream side rollers pair is conveying the medium, and   in the first conveying state, the first driving part retreats the first rib from the curved path, and the second driving part protrudes the second rib into the curved path, and   in the second conveying state, based on a fact that the detecting part detects conveying of the medium by the downstream side rollers pair, the first driving part protrudes the first rib into the curved path, and the second driving part retreats the second rib from the curved path.   
     
     
         7 . The medium guiding device according to  claim 1 , wherein, 
 the first rib and the second rib are cylindrical, and provided to be turnable around the axes in contact with the medium.   
     
     
         8 . An image forming device comprising the medium guiding device according to  claim 1 . 
     
     
         9 . An image reading device comprising the medium guiding device according to  claim 1 . 
     
     
         10 . A post-processing device comprising the medium guiding device according to  claim 1 .