Sheet carrying apparatus having sheet pressing mechanism, and sheet carrying method using sheet carrying mechanism

Abstract

A sheet carrying apparatus having a sheet pressing mechanism according to an embodiment of the invention includes: a paper supply tray in which sheets for printing an image thereon are stacked; a pickup roller which is abutted from above against a sheet on a top layer of the sheets stacked in the paper supply tray, then rotates and move the sheet on the top side; and a holding plate which presses the top layer sheet from above in a part where the pickup roller is abutted against the top layer sheet.

1 . A sheet carrying apparatus having a sheet pressing mechanism, comprising:
 a paper supply tray in which sheets for printing an image thereon are stacked;   a pickup roller which is abutted from above against a sheet on a top layer of the sheets stacked in the paper supply tray, then rotates and move the sheet on the top side; and   a holding plate which presses the top layer sheet from above in a part where the pickup roller is abutted against the top layer sheet.   
     
     
         2 . The apparatus according to  claim 1 , wherein the holding plate presses the top layer sheet from above by its own weight. 
     
     
         3 . The apparatus according to  claim 2 , wherein the holding plate is abutted against the top layer sheet in a part that is not the part where the pickup roller is abutted against the top layer sheet. 
     
     
         4 . The apparatus according to  claim 3 , wherein the holding plate is abutted against the top layer sheet in a part that is not the part where the pickup roller is abutted against the top layer sheet and closer to an edge in a moving direction of the top layer sheet. 
     
     
         5 . The apparatus according to  claim 4 , wherein the holding plate has a structure such that the holding plate is abutted against the top layer sheet substantially at right angles to the moving direction of the top layer sheet and with a turning edge turning about a supporting shaft provided near an edge of the top layer sheet. 
     
     
         6 . The apparatus according to  claim 5 , wherein a part of a cross-section of the turning edge to be abutted against the top layer sheet has a downward curved shape. 
     
     
         7 . The apparatus according to  claim 6 , wherein the holding plate has such a shape that a part where the pickup roller is abutted against the top layer sheet is cut out. 
     
     
         8 . The apparatus according to  claim 7 , wherein the turning edge of the holding plate has a shape including two sides slanting in the direction of the supporting shaft from a central part. 
     
     
         9 . The apparatus according to  claim 7 , wherein the holding plate has a U-shape. 
     
     
         10 . The apparatus according to  claim 9 , wherein the holding plate has a groove parallel to the moving direction of the top layer sheet, on a side to be abutted against the top layer sheet. 
     
     
         11 . The apparatus according to  claim 10 , wherein the holding plate is fixed and held at a predetermined position before the sheets are supplied to the paper supply tray, and the fixation and holding of the holding plate is canceled after the sheets are supplied to the paper supply tray. 
     
     
         12 . The apparatus according to  claim 11 , wherein the fixation and holding of the holding plate is carried out by a tension spring and a solenoid provided above the holding plate. 
     
     
         13 . The apparatus according to  claim 12 , wherein the paper supply tray rises after reuse sheets are supplied to the paper supply tray, and the pickup roller rotates after the holding plate is abutted against the top layer sheet. 
     
     
         14 . A sheet carrying method using a sheet pressing mechanism, comprising:
 pressing a sheet on a top layer of sheets stacked in a paper supply tray in which sheets for printing an image thereon are stacked, from above by a holding plate; and   abutting a pickup roller against the sheet on the top layer from above and rotating the pickup roller, in a part that is not pressed by the holding plate, and thus moving the top layer sheet.   
     
     
         15 . The method according to  claim 14 , further comprising:
 stopping the rotation of the pickup roller when the sheets housed in the paper supply tray are gone;   fixing and holding the holding plate;   after moving the paper supply tray downward and supplying sheets, moving the paper supply tray upward and stopping the paper supply tray in a state of being abutted against the pickup roller;   canceling the fixation and holding of the holding plate; and   rotating the pickup roller and moving the top layer sheet.   
     
     
         16 . The method according to  claim 15 , wherein the holding plate is abutted against the top layer sheet in a part that is not the part where the pickup roller is abutted against the top layer sheet and closer to an edge in a moving direction of the top layer sheet. 
     
     
         17 . The method according to  claim 16 , wherein the holding plate has such a structure that the holding plate is abutted against the top layer sheet substantially at right angles to the moving direction of the top layer sheet and with a turning edge turning about a supporting shaft provided near an edge of the top layer sheet. 
     
     
         18 . The method according to  claim 17 , wherein the holding plate has a part of a cross-section of the turning edge to be abutted against the top layer sheet that has a downward curved shape. 
     
     
         19 . The method according to  claim 18 , wherein the holding plate has a U-shape. 
     
     
         20 . The method according to  claim 19 , wherein the holding plate has a groove parallel to the moving direction of the top layer sheet, on a side to be abutted against the top layer sheet.