Image forming apparatus and cartridge group

A cartridge group comprising:

• a first cartridge including (i) a first photosensitive drum, (ii) a first drive input portion located at one end in a first axial direction of the first photosensitive drum, (iii) a first supporting member including a first supporting portion and a second supporting portion that support a side of the one end in the first axial direction of the first photosensitive drum in such a way as to allow the first photosensitive drum to rotate, and (iv) a first developing roller;
• and
• a second cartridge including (v) a second photosensitive drum, (vi) a second drive input portion located at one end in a second axial direction of the second photosensitive drum, (vii) a second supporting member including a third supporting portion and a fourth supporting portion that support a side of the one end in the second axial direction of the second photosensitive drum in such a way as to allow the second photosensitive drum to rotate, and (viii) a second developing roller,
• wherein, when an angle made by a straight line connecting a midpoint of a line segment connecting the first supporting portion and the second supporting portion and a rotational center of the first photosensitive drum with a straight line connecting the rotational center of the first photosensitive drum and a rotational center of the first developing roller as viewed from the first axial direction is referred to as a first angle, and an angle made by a straight line connecting a midpoint of a line segment connecting the third supporting portion and the fourth supporting portion and a rotational center of the second photosensitive drum with a straight line connecting the rotational center of the second photosensitive drum and a rotational center of the second developing roller as viewed from the second axial direction is referred to as a second angle, the first angle is different from the second angle.