Image forming apparatus and method for controlling feeding of sheets

A method for controlling feeding of a sheet in an image forming apparatus to which a paper-output device configured to process a sheet after image formation can be attached, the method comprising:

• sending information about processing to be performed by the paper-output device to the paper-output device, the information including information about sheet type preset to a paper-feed unit of the image forming apparatus and information to control the paper-output device configured to perform paper-output processing of a sheet after image formation;
• calculating a sheet-processing time used by the paper-output device based on the information about the processing to be performed by the paper-output device;
• determining a sheet-feed timing in the image forming apparatus the calculated sheet-processing time;
• and
• starting feeding of a sheet in accordance with the sheet-feed timing set in the determining.

A method for controlling feeding of a sheet in an image forming apparatus to which a paper-output device configured to process a sheet after image formation can be attached, the method comprising:

• sending information about processing to be performed by the paper-output device to the paper-output device, the information including information about sheet type preset to a paper-feed unit of the image forming apparatus;
• calculating a sheet-processing time used by the paper-output device based on the information about the processing to be performed by the paper-output device;
• detecting a type of a sheet fed from the paper-feed unit;
• renewing the sheet-processing time calculated in the calculating, if the sheet type preset to the paper-feed unit does not match the detected type of the sheet;
• and
• starting feeding of the sheet in accordance with the renewed sheet-processing time.