Patent ID: 11892791
Assignee: CANON KABUSHIKI KAISHA
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. An image forming apparatus comprising:
a rotatable photosensitive member;
a charging portion configured to electrically charge a surface of the photosensitive member;
an exposure portion configured to expose the charged surface of the photosensitive member to light to form an electrostatic latent image on the photosensitive member;
a developing member configured to develop the electrostatic latent image on the photosensitive member with toner into a toner image in contact with the surface of the photosensitive member;
a transfer unit configured to transfer the toner image from the photosensitive member onto a toner image receiving member in a transfer portion;
a contact and separation portion configured to move the developing member to a contact position where the developing member contacts the surface of the photosensitive member and a separated position where the developing member is separated from the surface of the photosensitive member;
a charging voltage applying portion configured to apply, to the charging portion, a charging voltage for charging the photosensitive member;
a detecting portion configured to detect the toner image, formed on the photosensitive member, on the photosensitive member or the toner image receiving member; and
a controller capable of controlling the contact and separation portion, the charging voltage applying portion, and the exposure portion,
wherein toner remaining on the photosensitive member without being transferred onto the toner image receiving member is collected by the developing member,
wherein the controller is capable of executing:
an operation in an image forming mode in which the controller carries out control so that the toner image to be formed on a recording material as the toner image receiving member or a recording material onto which the toner image is transferred from the toner image receiving member is formed, and
an operation in a detecting mode in which the controller carries out control so that a predetermined instruction to position the developing member in the separated position is sent to the contact and separation portion and an electrostatic latent image for a test pattern is formed on the photosensitive member and then so that in a case that the developing member is positioned in the contact position in accordance with the predetermined instruction without being positioned in the separated position, a toner image for the test pattern formed by developing the electrostatic latent image for the test pattern with toner is detected by the detecting portion, and
wherein the controller carries out control so that a charging current flowing through the charging portion during charging of the photosensitive member in the operation in the detecting mode is lower than a charging current flowing through the charging portion during charging of the photosensitive member in the operation in the image forming mode.