Detection system and inkjet recording apparatus

A detection system, comprising:

• a detection target device that includes a first rotating member rotatable about a first axis and that repeats an operation corresponding to a rotation angle of the first rotating member every time the first rotating member makes a 1/N rotation, N being an integer of 2 or greater;
• and
• a detection device that includes a second rotating member rotatable about a second axis due to a driving force transmitted from the first rotating member and of which an output value repeats monotonic increase or monotonic decrease in accordance with a rotation angle of the second rotating member every time the second rotating member makes 1 rotation,
• wherein
• every time the first rotating member makes a 1/N rotation, the second rotating member makes 1 rotation, and
• within a whole range of the output value of the detection device from a minimum value to a maximum value, a predetermined range where detection accuracy is guaranteed is assigned to a region corresponding to a 1/N rotation of the first rotating member.