Image forming apparatus and control method for the same

Abstract

An image forming apparatus is provided. Sheets, a plurality of which form a set, are contained in each of containers, and sheets are fed from the corresponding containers. If a first sheet to be fed is in the same layer as a second sheet that was fed from the containers last time, the first sheet is fed from a set that included the second sheet in the containers is fed. If the layer of the first sheet is higher than the layer of the second sheet that was fed from the containers last time, all remaining sheets in the set that included the second sheet are discharged from the containers.

1 . A control apparatus comprising:
 a first container unit for containing sheets, a plurality of which form a set;   a second container unit for containing sheets, a plurality of which form a set;   a feed control unit for performing control to feed a sheet from a first set in the first container unit, then a sheet from a first set in the second container unit, again a sheet from the first set in the first container unit, and then a sheet from a second set in the second container unit; and   a discharge control unit for performing control to discharge all remaining sheets in the first set in the second container unit after the sheet is fed from the first set in the second container unit and before the sheet is fed again from the first set in the first container unit.   
     
     
         2 . A control apparatus comprising:
 a first container unit for containing sheets, a plurality of which form a set;   a second container unit for containing sheets, a plurality of which form a set;   a feed control unit for performing control to feed a sheet from a first set in the first container unit, then a sheet from a first set in the second container unit, again a sheet from the first set in the first container unit, and then a sheet from a second set in the second container unit; and   a discharge control unit for performing control to discharge all remaining sheets in the first set in the second container unit after the sheet is fed again from the first set in the first container unit and before the sheet is fed from the second set in the second container unit.   
     
     
         3 . An image forming apparatus comprising:
 a plurality of container units each containing sheets, a plurality of which form a set, the plurality of container units containing sheets of different layers respectively;   a feed control unit for performing control to feed, if a first sheet to be fed is in the same layer as a second sheet that was fed from the plurality of container units last time, the first sheet from the set that included the second sheet in the plurality of container units; and   a discharge control unit for performing control to discharge, if the layer of the first sheet to be fed is higher than the layer of the second sheet that was fed from the plurality of container units last time, all remaining sheets in the set that included the second sheet from the plurality of container units before the first sheet is fed from the plurality of container units.   
     
     
         4 . An image forming apparatus comprising:
 a plurality of container units each containing sheets, a plurality of which form a set, the plurality of container units containing sheets of different layers respectively;   a feed control unit for performing control to feed, if a first sheet to be fed is in the same layer as a sheet that was fed from the plurality of container units last time, the first sheet from the set that included the second sheet in the plurality of container units; and   a discharge control unit for performing control to discharge, if the layer of the first sheet to be fed is higher than the layer of the second sheet that was fed from the plurality of container units last time, all remaining sheets in the set that included the second sheet from the plurality of container units after the first sheet is fed from the plurality of container units.   
     
     
         5 . The image forming apparatus according to  claim 3 , wherein the discharge control unit, after a job ends, discharges all remaining sheets in currently used sets that include the first and second sheets from the plurality of container units. 
     
     
         6 . The image forming apparatus according to  claim 3  further comprising a sheet feeding tray table for storing a type, size, and the number of sheets per set of the sheets contained in each of the plurality of container units. 
     
     
         7 . The image forming apparatus according to  claim 3  further comprising an index sheet management table for storing a type, layer, size, the number of sheets per set, and the number of already used sheets in a currently used set of the sheets in the plurality of container units,
 wherein the feed control unit and the discharge control unit updates the index sheet management table in accordance with feed and discharge of the sheets. 
 
     
     
         8 . The image forming apparatus according to  claim 7 , wherein the index sheet management table further has a flag for each type of sheets, the flag being designed to indicate whether or not to discharge remaining sheets in the currently used set of the sheets contained in the plurality of container units. 
     
     
         9 . A control method for controlling an image forming apparatus including a plurality of container units each containing sheets, a plurality of which form a set, the plurality of container units containing sheets of different layers respectively, the method comprising:
 a feed control step of feeding, if a first sheet to be fed is in the same layer as a second sheet that was fed from the plurality of container units last time, the first sheet from a set that included the second sheet in the plurality of container units; and   a discharge control step of discharging, if the layer of the first sheet to be fed is higher than the layer of the second sheet that was fed from the plurality of container units last time, all remaining sheets in the set that included the second sheet from the plurality of container units before the first sheet is fed from the plurality of container units.   
     
     
         10 . A control method for controlling an image forming apparatus including a plurality of container units each containing sheets, a plurality of which form a set, the plurality of container units containing sheets of different layers respectively, the method comprising:
 a feed control step of feeding, if a first sheet to be fed is in the same layer as a second sheet that was fed from the plurality of container units last time, the first sheet from a set that included the second sheet in the plurality of container units; and   a discharge control step of discharging, if the layer of the first sheet to be fed is higher than the layer of the second sheet that was fed from the plurality of container units last time, all remaining sheets in the set that included the second sheet from the plurality of container units after the first sheet is fed from the plurality of container units.