Sheet processing apparatus, control method of sheet processing apparatus, and storage medium

A control method for controlling a sheet processing apparatus, the method comprising:

• inserting an insert sheet fed from a second sheet holding unit in a plurality of sheets fed from a first sheet holding unit, and causing a saddle stitch bookbinding device to execute a saddle stitch bookbinding process to the plurality of sheets in which the insert sheet has been inserted;
• judging whether or not a position in which it has been designated to insert the insert sheet is a position in which the insert sheet can be inserted;
• and
• in a case where it is judged that the position in which it has been designated to insert the insert sheet is not the position in which the insert sheet can be inserted, controlling the saddle stitch bookbinding device not to execute the saddle stitch bookbinding process to the plurality of sheets in which the insert sheet has been inserted.

A non-transitory computer readable storage medium for storing a computer program for controlling a sheet processing apparatus, the computer program comprising:

• code to insert an insert sheet fed from a second sheet holding unit in a plurality of sheets fed from a first sheet holding unit, and cause a saddle stitch bookbinding device to execute a saddle stitch bookbinding process to the plurality of sheets in which the insert sheet has been inserted;
• code to judge whether or not a position in which it has been designated to insert the insert sheet is a position in which the insert sheet can be inserted;
• and
• code to, in a case where it is judged that the position in which it has been designated to insert the insert sheet is not the position in which the insert sheet can be inserted, control the saddle stitch bookbinding device not to execute the saddle stitch bookbinding process to the plurality of sheets in which the insert sheet has been inserted.