Image forming apparatus, image forming system and program for image forming

An image forming system, comprising:

• an image forming apparatus which includes an image forming section forming an image on a recording medium based on input data;
• and
• a post-processing apparatus including a post-processing section which post-processes the recording medium after the image is formed on the recording medium by the image forming apparatus,
• wherein the image forming system includes
• a first supply section which supplies a special sheet of a first special sheet group, the first special sheet group including first special sheet sets, each set of which containing a plurality of different kind of special sheets arranged in a predetermined order;
• a second supply section which supplies a special sheet of a second special sheet group, the special sheet of the second special sheet group being to be inserted between sheets of the first special sheet group, the second special sheet group including second special sheet sets, each set of which containing a plurality of different kind of special sheets arranged in a predetermined order;
• a stacking section which stacks the special sheet supplied by the first supply section and the special sheet supplied by the second supply section;
• a conveyance section which conveys at least one sheet of the second special sheet group so as to be inserted between two special sheets supplied by the first supply section on the stacking section;
• and
• a control section which controls the second supply section and the conveyance section so that a rest of special sheets which belong to the same set as a special sheet having been last supplied by the second supply section is supplied by the second supply section and is ejected to a sheet ejection destination other than the stacking section before a special sheet of the second special sheet group is inserted after the latter sheet of the two special sheets supplied by the first supply section.