Image Forming Apparatus

Abstract

An image forming apparatus includes a plurality of paper sheet feeders, a conveying unit, an image forming unit, and a control unit. The plurality of paper sheet feeders each include an opening/closing detection unit and a sheet information detecting unit. The opening/closing detection unit detects opening and closing of the paper sheet feeder. The sheet information detecting unit detects sheet information. The sheet information indicates information regarding a sheet housed in the paper sheet feeder. When the opening/closing detection unit detects that the paper sheet feeder is closed after detecting that the paper sheet feeder was opened, the control unit: determines whether the sheet information has changed from before and after opening and closing the paper sheet feeder or not, and determines whether to switch the selected paper sheet feeder or not based on the determination result.

What is claimed is: 
     
         1 . An image forming apparatus comprising:
 a plurality of paper sheet feeders configured to each house sheets, the plurality of paper sheet feeders being openable/closable;   a conveying unit that conveys a sheet from a paper sheet feeder selected among the plurality of paper sheet feeders;   an image forming unit that forms an image on the sheet conveyed by the conveying unit; and   a control unit that controls the paper sheet feeder, the image forming unit, and the conveying unit,   wherein the plurality of paper sheet feeders each include:
 an opening/closing detection unit that detects opening and closing of the paper sheet feeder; and 
 a sheet information detecting unit that detects sheet information, 
   wherein the sheet information indicates information regarding a sheet housed in the paper sheet feeder, and
 when the opening/closing detection unit detects that the paper sheet feeder is closed after detecting that the paper sheet feeder was opened, 
 the control unit:
 determines whether the sheet information has changed from before and after opening and closing the paper sheet feeder or not, and 
 determines whether to switch the selected paper sheet feeder or not based on the determination result. 
 
   
     
     
         2 . The image forming apparatus according to  claim 1 ,
 wherein when the sheet information has been determined to be changed from before and after opening and closing the paper sheet feeder, the control unit determines whether the paper sheet feeder the sheet information of which has changed matches the selected paper sheet feeder or not,   when the paper sheet feeder the sheet information of which had changed has been determined to fail to match the selected paper sheet feeder, the control unit switches the selected paper sheet feeder to the paper sheet feeder the sheet information of which has changed.   
     
     
         3 . The image forming apparatus according to  claim 1 , further comprising
 a display that displays a confirmation image,   wherein when the sheet information has been determined to be changed from before and after opening and closing the paper sheet feeder, the control unit displays the confirmation image on the display, and   the confirmation image is an image to confirm whether to switch the selected paper sheet feeder or not.   
     
     
         4 . The image forming apparatus according to  claim 1 ,
 wherein the sheet information detecting unit detects a size of a sheet housed in the paper sheet feeder as the sheet information.   
     
     
         5 . The image forming apparatus according to  claim 1 ,
 wherein the sheet information detecting unit detects an orientation of a sheet housed in the paper sheet feeder as the sheet information.   
     
     
         6 . The image forming apparatus according to  claim 1 ,
 wherein the sheet information detecting unit detects an amount of sheets housed in the paper sheet feeder as the sheet information.   
     
     
         7 . The image forming apparatus according to  claim 1 , further comprising
 a storage unit that stores an accumulated count of the sheet on which an image is formed,   wherein the control unit:
 determines whether the sheet housed in the paper sheet feeder is gone or not, and 
 switches the selected paper sheet feeder based on the accumulated count when the sheet housed in the paper sheet feeder has been determined to be gone. 
   
     
     
         8 . The image forming apparatus according to  claim 7 ,
 wherein the storage unit stores the accumulated counts for the respective plurality of paper sheet feeders,   the control unit:
 determines whether the sheet housed in the paper sheet feeder is gone or not, and 
 switches the selected paper sheet feeder to a paper sheet feeder the accumulated count of which is most among the plurality of paper sheet feeders when the sheet housed in the paper sheet feeder has been determined to be gone. 
   
     
     
         9 . The image forming apparatus according to  claim 7 ,
 wherein the storage unit stores the accumulated counts for each size of a sheet, and   when the sheet housed in the paper sheet feeder has been determined to be gone, the control unit switches the selected paper sheet feeder to a paper sheet feeder that corresponds to a size of a sheet the accumulated count of which is most among the plurality of paper sheet feeders.