Sheet conveyance device and image forming apparatus therefor

Abstract

A sheet conveyance device includes a pair of conveyance rollers, a contact-release mechanism, an alignment mechanism, and a control portion. The contact-release mechanism moves first and second conveyance rollers, constituting the pair of conveyance rollers, into contact with and away from each other. The alignment mechanism aligns a sheet conveyed along the sheet conveyance passage in a sheet width direction. The alignment mechanism includes a pair of alignment members movable toward and away from each other in the sheet width direction and aligning the sheet in the sheet width direction by making contact, from both sides in the sheet width direction, with side edges of the sheet. The control portion controls the contact-release mechanism to move the first and second conveyance rollers away from each other, and aligns the sheet with the pair of alignment members located opposite each other in the sheet width direction.

What is claimed is: 
     
         1 . A sheet conveyance device, comprising:
 a pair of conveyance rollers which conveys a sheet along a sheet conveyance passage;   a contact-release mechanism which moves first and second conveyance rollers, constituting the pair of conveyance rollers, into contact with and away from each other;   an alignment mechanism which aligns the sheet conveyed along the sheet conveyance passage at a predetermined alignment position in a sheet width direction orthogonal to the sheet conveyance direction; and   a control portion which controls the pair of conveyance rollers, the contact-release mechanism, and the alignment mechanism,   wherein   the alignment mechanism includes a pair of alignment members movable toward and away from each other in the sheet width direction, the alignment members aligning the sheet in the sheet width direction by making contact, from both sides in the sheet width direction, with side edges of the sheet conveyed along the sheet conveyance passage, and   the control portion controls the contact-release mechanism to move the first and second conveyance rollers away from each other, and aligns the sheet with the pair of alignment members located opposite each other in the sheet width direction.   
     
     
         2 . The sheet conveyance device according to  claim 1 , wherein
 the pair of alignment members include:
 a first pair of alignment members disposed downstream in the sheet conveyance direction, located opposite each other in the sheet width direction and making contact, from both sides in the sheet width direction, with downstream side edges of the sheet, and 
 a second pair of alignment members disposed upstream in the sheet conveyance direction, located opposite each other in the sheet width direction and making contact, from both sides in the sheet width direction, with upstream side edges of the sheet. 
   
     
     
         3 . The sheet conveyance device according to  claim 1 , wherein
 the pair of alignment members include:
 a first alignment member disposed at one side in the sheet width direction and making contact with a side edge of the sheet, 
 a second alignment member disposed at another side in the sheet width direction, downstream in the sheet conveyance direction, opposite the first alignment member in the sheet width direction, the second alignment member making contact with a downstream side edge of the sheet, 
 a third alignment member disposed at another side in the sheet width direction, upstream in the sheet conveyance direction, opposite the first alignment member in the sheet width direction, the third alignment member making contact with an upstream side edge of the sheet. 
   
     
     
         4 . The sheet conveyance device according to  claim 1 , further comprising:
 driving motors which move the pair of alignment members located opposite each other in the sheet width direction independently of each other in the sheet width direction, and   urging members which urge the pair of alignment members located opposite each other in the sheet width direction independently of each other in a direction away from the sheet.   
     
     
         5 . The sheet conveyance device according to  claim 4 , wherein
 the pair of alignment member includes
 a one-side alignment member disposed at the one side in the sheet width direction, and 
 an other-side alignment member disposed at the other side in the sheet width direction, 
   the alignment mechanism further includes
 a sheet pressing member which is attached to the one-end side aligning member and is configured to press an upper surface of the sheet at the one side in the sheet width direction, and 
   the control portion, after controlling the alignment mechanism to align the sheet,
 controls the sheet pressing member to press the sheet at the one side in the sheet width direction, 
 moves the other-side alignment member away from a side edge of the sheet, 
 controls the contact-release mechanism to move the first and second conveyance rollers into contact with each other, and 
 cancels pressing of the sheet by the sheet pressing member. 
   
     
     
         6 . The sheet conveyance device according to  claim 1 , wherein
 the sheet conveyance passage includes a plurality of the sheet conveyance passages, and   the plurality of the sheet conveyance passages each include the pair of conveyance rollers, the contact-release mechanism, and the alignment mechanism.   
     
     
         7 . The sheet conveyance device according to  claim 6 , wherein
 the plurality of sheet conveyance passages include:
 a feeding sheet conveyance passage which extends from a sheet feed portion which stores the sheet to a recording portion which records an image to the sheet, and 
 a duplex sheet conveyance passage which conveys the sheet having the image recorded thereto at the recording portion once again to the recording portion. 
   
     
     
         8 . The sheet conveyance device according to  claim 7 , wherein
 the feeding sheet conveyance passage includes a first sheet conveyance passage and a second conveyance passage which are disposed side by side in the sheet conveyance direction and along which the sheet is selectively conveyed.   
     
     
         9 . The sheet conveyance device according to  claim 8 , wherein
 the second sheet conveyance passage and the duplex sheet conveyance passage meet at a confluence portion downstream in the sheet conveyance direction, and   the alignment portion is disposed in the confluence portion.   
     
     
         10 . An image forming apparatus, comprising:
 the sheet conveyance device according to  claim 1 , and   an image forming portion which forms an image on the sheet conveyed by the sheet conveyance device,   wherein   the alignment portion is disposed closely upstream of the image forming portion in the sheet conveyance direction.