Image forming apparatus and image forming system

An image forming apparatus, which has a receiving portion configured to receive sheets from outside, the image forming apparatus being operable in a first configuration in which a conveying path of a first sheet feeding apparatus is connected to the receiving portion of the image forming apparatus and a second configuration in which a conveying path of a sheet conveying apparatus is connected to the receiving portion of the image forming apparatus and a second sheet feeding apparatus is connected to the sheet conveying apparatus on an upstream side with respect to a sheet conveying direction, the first sheet feeding apparatus comprising a first control unit configured to control conveyance of a sheet and being configured to temporarily stop the conveyance of the sheet within the conveyance path thereof, the second sheet feeding apparatus comprising a second control unit configured to control conveyance of a sheet and being configured not to temporarily stop the conveyance of a sheet within a conveyance path thereof, the sheet conveying apparatus comprising a third control unit configured to control conveyance of a sheet, being configured to receive the sheet from the second sheet feeding apparatus, and being configured to temporarily stop the conveyance of the sheet in the conveyance path within the sheet conveying apparatus, and the image forming apparatus being configured to form an image on the sheet fed from the first sheet feeding apparatus in the first configuration and the image forming apparatus being configured to form an image on the sheet fed from the second sheet feeding apparatus through the sheet conveying apparatus in the second configuration, the image forming apparatus comprising:

• an image former configured to form an image on the sheet based on a print job;
• an obtaining device configured to obtain apparatus information corresponding to whether the image forming apparatus is operated in the first configuration or the second configuration;
• and
• a controller configured to determine, based on the apparatus information obtained by the obtaining device, timings to send a feed request for starting to feed the sheet and a delivery request for instructing to deliver the sheet,
• wherein the receiving portion to which the sheet conveying apparatus is connected is common to the receiving portion to which the first sheet feeding apparatus is connected,
• wherein in a case in which the image forming apparatus is operated in the first configuration and forms the image on the sheet fed from the first sheet feeding apparatus, the controller sends the feed request to the first sheet feeding apparatus, sends to the first control unit the delivery request for a first sheet fed according to the feed request and temporarily stopped at a first predetermined position in the first sheet feeding apparatus, and sends to the first control unit the feed request for a second sheet subsequent to the first sheet at a timing coincident with a sending timing of the delivery request or at a timing before the sending timing of the delivery request, and
• wherein in a case in which the image forming apparatus is operated in the second configuration and forms the image on the sheet fed from the second sheet feeding apparatus, the controller sends the feed request to the second sheet feeding apparatus, sends to the third control unit the delivery request for a third sheet fed according to the feed request and temporarily stopped at a second predetermined position in the sheet conveying apparatus, and sends the feed request for a fourth sheet to the second sheet feeding apparatus at such a timing as to cause the fourth sheet to be conveyed to the sheet conveying apparatus at a timing at which the third sheet is conveyed from the sheet conveying apparatus to the image forming apparatus.