An image forming apparatus includes a unit horizontally insertable and drawable with respect to a main body frame, and a lock mechanism for the unit. The lock mechanism includes a lock member which has an engagement projection engageable with an engaged portion formed in the main body frame, and a biasing member which biases the lock member in a first direction toward engagement of the engagement projection with the engaged portion. Along with insertion of the unit, the lock member moves in a second direction, and when the unit is inserted to a predetermined position, biasing force of the biasing member causes the lock member to move in the first direction and the engagement projection engages with the engaged portion. By moving the lock member in the second direction, engagement between the engagement projection and the engaged portion is released to make it possible to draw the unit.

An image forming apparatus that forms an image on a sheet under an operation condition set depending on a sheet type, includes a hardware processor that: detects whether the sheet type is any one of a plurality of assumed types; performs control such that an activation operation for forming the image under an interim condition, which is an operation condition corresponding to one of the plurality of assumed types, is performed before detecting the sheet type; determines whether or not a recovery operation for optimizing a state of image formation is performed before starting image formation under a determinate condition, which is an operation condition corresponding to the detected type; performs control such that the recovery operation is performed when it is determined that the recovery operation is performed; and performs control such that the image formation is performed under the determinate condition after the recovery operation is performed.

An image forming apparatus that forms an image on a sheet under an operation condition set depending on a sheet type, includes a hardware processor that: detects whether the sheet type is any one of a plurality of assumed types; performs control such that an activation operation for forming the image under an interim condition, which is an operation condition corresponding to one of the plurality of assumed types, is performed before detecting the sheet type; determines whether or not a recovery operation for optimizing a state of image formation is performed before starting image formation under a determinate condition, which is an operation condition corresponding to the detected type; performs control such that the recovery operation is performed when it is determined that the recovery operation is performed; and performs control such that the image formation is performed under the determinate condition after the recovery operation is performed.

An image forming apparatus includes a unit horizontally insertable and drawable with respect to a main body frame, and a lock mechanism for the unit. The lock mechanism includes a lock member which has an engagement projection engageable with an engaged portion formed in the main body frame, and a biasing member which biases the lock member in a first direction toward engagement of the engagement projection with the engaged portion. Along with insertion of the unit, the lock member moves in a second direction, and when the unit is inserted to a predetermined position, biasing force of the biasing member causes the lock member to move in the first direction and the engagement projection engages with the engaged portion. By moving the lock member in the second direction, engagement between the engagement projection and the engaged portion is released to make it possible to draw the unit.