Image forming apparatus

Abstract

An image forming apparatus includes an image forming portion, an oblique movement correcting portion including a first registration roller pair and a first moving portion, a reversing portion, and a re-feeding portion. The reversing portion includes a reversing roller pair and a second moving portion. The re-feeding portion includes a second registration roller pair. When an image is formed on a second surface of a sheet opposite from a first surface of the sheet, a side end position of the sheet is corrected by the second moving portion and oblique movement of the sheet is corrected, and then the side end position of the sheet is corrected again by the first moving means and the sheet is fed to the image forming portion.

1 - 13  (canceled) 
     
     
         14 . An image forming apparatus comprising:
 an image forming portion configured to form an image on a sheet;   a first conveying roller pair configured to nip and convey the sheet on which the image is formed on a first surface by the image forming portion;   a first moving portion configured to move the sheet in a widthwise direction of the sheet perpendicular to a feeding direction of the sheet in a state in which the sheet is nipped by the first conveying roller pair;   a second conveying roller pair disposed upstream of the image forming portion in the feeding direction, and configured to nip and convey the sheet to form, by the image forming portion, an image on a second surface of the sheet opposite to the first surface of the sheet; and   a second moving portion configured to move the sheet nipped by the second conveying roller pair in the widthwise direction, after the sheet is moved in the widthwise direction by the first moving portion.   
     
     
         15 . An image forming apparatus according to  claim 14 , further comprising:
 a first detecting portion provided upstream of the first conveying roller pair with respect to the feeding direction and configured to detect a position of the sheet with respect to the widthwise direction; and   a second detecting portion provided upstream of the second conveying roller pair with respect to the feeding direction and configured to detect the position of the sheet with respect to the widthwise direction,   wherein the first moving portion moves the sheet nipped by the first conveying roller pair with respect to the feeding direction based on a detection result of the first detecting portion, and   wherein the second moving portion moves the sheet nipped by the second conveying roller pair with respect to the feeding direction based on a detection result of the second detecting portion.   
     
     
         16 . An image forming apparatus according to  claim 14 , wherein the first conveying roller pair is a first reversing roller pair configured to reverse the sheet by rotating in a first direction while nipping the sheet on which the image is formed on the first surface by the image forming portion and then by rotating in a second direction opposite to the first direction. 
     
     
         17 . An image forming apparatus according to  claim 16 , further comprising a second reversing roller pair provided downstream of the first reversing roller pair with respect to the feeding direction and configured to reverse the sheet by rotating in the first direction while nipping the sheet on which the image is formed on the first surface by the image forming portion and then by rotating in the second direction opposite to the first direction,
 wherein the first moving portion moves the sheet nipped by both the first reversing roller pair and the second reversing roller pair with respect to the widthwise direction.   
     
     
         18 . An image forming apparatus according to  claim 16 , further comprising a re-feeding portion configured to feed the sheet reversed by the first reversing roller pair toward the second conveying roller pair,
 wherein the second conveying roller pair is disposed downstream of the re-feeding portion and upstream of the image forming portion with respect to the feeding direction.   
     
     
         19 . An image forming apparatus according to  claim 18 , wherein the second conveying roller pair is a first registration roller pair configured to correct oblique movement of the sheet conveyed by the first conveying roller pair. 
     
     
         20 . An image forming apparatus according to  claim 19 , wherein the first conveying roller pair ( 1 ) includes a first roller and a second roller which are rotatable about shafts thereof extending in the widthwise direction, respectively, and ( 2 ) moves in the widthwise direction in a state in which the sheet is nipped by the first roller and the second roller,
 wherein the first registration roller pair ( 1 ) includes a third roller and a fourth roller which are rotatable about shafts thereof extending in the widthwise direction, respectively, and ( 2 ) moves in the widthwise direction in a state in which the sheet is nipped by the third roller and the fourth roller, and   wherein a number of a second nip portion formed by the third roller and the fourth roller where the sheet is nipped is more than a number of a first nip portion formed by the first roller and the second roller where the sheet is nipped.   
     
     
         21 . An image forming apparatus according to  claim 19 , wherein the re-feeding portion includes a second registration roller pair configured to correct oblique movement of the sheet reversed by the first reversing roller pair. 
     
     
         22 . An image forming apparatus according to  claim 14 , further comprising:
 a first casing including ( 1 ) the image forming portion, ( 2 ) the second conveying roller pair, and ( 3 ) the second moving portion; and   a second casing including ( 1 ) the first conveying roller pair and ( 2 ) the first moving portion, and connected to the first casing.