An image forming apparatus includes a first process unit and a second process unit. The first process unit includes: a first photosensitive member configured to carry a first developer image to be transferred onto a transfer medium; and a blade member configured to scrape substances attached to a surface of the first photosensitive member off the surface of the first photosensitive member. The second process unit includes: a second photosensitive member configured to carry a second developer image to be transferred onto the transfer medium having the first developer image transferred thereon; and a holding member configured to remove substances attached to a surface of the second photosensitive member from the surface of the second photosensitive member, temporarily hold the substances and return the substances to the surface of the second photosensitive member.