Sheet feeder in image forming apparatus

Abstract

A sheet feeder in an image forming apparatus of this invention is provided with special sheet ribs for controlling both sides of special sheet on a sheet guide provided between a manual sheet supply tray and aligning rollers. This is to satisfactorily guide ordinary sheet and special sheet such as post card supplied from manual sheet supply trays to aligning rollers which conveys sheet vertically. When special sheet is conveyed, the sheet is inserted between the special sheet ribs to prevent skew. When ordinary sheet is conveyed, the sheet is passed above the upper surface of the special ribs so as to prevent generation of defective image caused by bending of sheet.

1 . A sheet feeder in an image forming apparatus comprising: 
 a manual sheet supply unit to supply special sheet and sheet other than the special sheet;    a conveying member to convey the special sheet and the sheet other than special sheet supplied from the manual sheet supply unit toward an image forming process unit; and    a sheet guide provided between the manual sheet supply unit and the conveying member, having special sheet ribs to control both sides of the special sheet that is inserted and guided the special sheet ribs and the sheet other than the special sheet is guided by passing the upper surface of the special sheet ribs.    
   
   
       2 . The sheet feeder in an image forming apparatus according to  claim 1 , wherein mass of the special sheet is larger than mass of the sheet other than the special sheet.  
   
   
       3 . The sheet feeder in an image forming apparatus according to  claim 1 , wherein the manual sheet supply unit supplies the special sheet and the sheet other than the special sheet in a horizontal direction, and the conveying member conveys the special sheet and the sheet other than the special sheet in a vertical direction.  
   
   
       4 . The sheet feeder of in image forming apparatus according to  claim 1 , wherein the sheet guide further has a pressing member between the special sheet ribs supports back of the sheet other than the special sheet by pressing and descends when the special sheet is inserted between the ribs.  
   
   
       5 . The sheet conveying apparatus in an image forming apparatus according to  claim 4 , wherein the pressing member is made of a compressed Mylar™ that descent by an empty weight of the special sheet when the special sheet is inserted.  
   
   
       6 . A sheet feeder in an image forming apparatus comprising: 
 a manual sheet supply unit to supply special sheet and sheet other than the special sheet on a manual sheet supply tray;    aligning rollers to align the leading edges of the special sheet and othe sheet other than the special sheet supplied from the manual sheet supply unit and convey in the image forming direction; and    a sheet guide provided between the manual sheet supply unit and the aligning rollers, having special sheet ribs to control both sides of the special sheet that is inserted and guided between the special sheet ribs and the sheet other than the special sheet is guided by passing the upper surfaces of the special sheet ribs.    
   
   
       7 . The sheet feeder in an image forming apparatus according to  claim 6 , wherein mass of the special sheet is larger than mass of the sheet other than the special sheet.  
   
   
       8 . The sheet feeder in an image forming apparatus according to  claim 6 , wherein the manual sheet supply unit supplies the special sheet and the sheet other than the special sheet in a horizontal direction, and the aligning rollers convey the special sheet and the sheet other than the special sheet in a vertical direction.  
   
   
       9 . The sheet feeder in an image forming apparatus according to  claim 6 , wherein the sheet guide further has a pressing member between the special sheet ribs supports back of the sheet other than the special sheet by pressing and descends when the special sheet is inserted between the ribs.  
   
   
       10 . The sheet feeder in an image forming apparatus according to  claim 9 , wherein the pressing member is made of a pressing Mylar™ that descent by an empty weight of the special sheet when the special sheet is inserted.