FIELD

Embodiments described herein relate to an image forming apparatus.

BACKGROUND

An image forming apparatus including an automatic document feeder (ADF) and a scanner is known. The image forming apparatus prints sheets of paper or the like based on a printing request and outputs printed sheets. The automatic document feeder conveys documents comprising multiple printed sheets sheet-by-sheet past a reading position of a scanner. The scanner optically reads the sheets conveyed by the document feeder and outputs image signals corresponding to the sheets.

The automatic document feeder includes a passage sensor. The passage sensor detects the passage of the sheets of the document along a conveyance path upstream of a reading position of the scanner, that is, portion of the conveyance path from insertion port of the document to reading position. The document feeder is thus able to detect when document sheet is not properly conveyed but stays or becomes stuck (jammed) along the conveyance path of the document feeder. That is, the occurrence of a feeding jam or the like can be detected by the passage sensor.

If a jam occurs, the image signal output from the scanner becomes abnormal. Therefore, the image forming apparatus must determine whether image data generated based on an image signal is corresponding to when the jam was detected. The image forming apparatus performs control so that the image data is not output if a jam is detected and is output if no jam is detected.

However, there can be a problem in that it is possible that image data generated based on an abnormal image signal has already been output before the jam is detected.

