Image forming apparatus including a cam member to separate a transfer member

摘要

An image forming apparatus includes an image forming unit; an intermediate transfer member; a secondary transfer member to form a secondary transfer nip with the intermediate transfer member and the secondary transfer member; a biasing mechanism to bias the secondary transfer member toward the intermediate transfer member; a cam member rotatable between a first position, at which a predetermined space is formed in the secondary transfer nip, and a second position, at which the secondary transfer member and the intermediate transfer member contact each other; and a contact-separation controller configured to put the cam member in the first position before entry of the recording medium into the secondary transfer nip, rotate the cam member toward the second position when the recording medium enters the secondary transfer nip, and change a start timing of rotation of the cam member in accordance with a thickness of the recording medium.

主权项

1. An image forming apparatus, comprising:
an image forming unit to form a toner image on an image carrier; an intermediate transfer member to which the toner image formed on the image carrier is transferred in a primary transfer; a secondary transfer member to form a secondary transfer nip with the intermediate transfer member and the secondary transfer member and transfer the toner image on the intermediate transfer member to a recording medium when the recording medium passes through the secondary transfer nip in a secondary transfer; a biasing mechanism to bias the secondary transfer member toward the intermediate transfer member; a cam member that is rotatable between a first position, at which the secondary transfer member is separated from the intermediate transfer member to form a predetermined space in the secondary transfer nip, and a second position, at which the secondary transfer member and the intermediate transfer member contact each other; and a contact-separation controller configured to: put the cam member in the first position to form the predetermined space in the secondary transfer nip before entry of the recording medium into the secondary transfer nip; rotate the cam member toward the second position when the recording medium enters the secondary transfer nip; and change a start timing of rotation of the cam member in accordance with a thickness of the recording medium, the contact-separation controller is configured to rotate the cam member from the first position to the second position when a front end of the recording medium approaches the secondary nip based on a thickness of the recording medium and configured to rotate the cam member from the second position to the first position when a rear end of the recording medium is exiting the secondary transfer nip, without regard for the thickness of the recording medium, and form the space in the secondary transfer nip at a point in which the rear end of the recording medium exits the secondary transfer nip.