Transfer device with contact pressure adjustment mechanism and image forming device using the same

1. A transfer device comprising:

a rotatable transfer roller capable coming into pressure contact with a belt-shaped intermediate transfer member; and

a controller that is provided at an end of the transfer roller in an axial direction thereof and that controls a balance of a pressure contact force exerted on the transfer roller in the axial direction,

the controller including: a bearing member that rotatably supports the end of the transfer roller in the axial direction; a movable holding section that holds the bearing member by way of an elastic member forced in a direction of pressure contact and is able to move along the direction of pressure contact; and a stationary holding section that has a guide section for guiding the movable holding section in the direction of pressure contact and that holds the movable holding section so as to be relatively movable,

the movable holding section and the stationary holding section opposing each other by way of opposed surfaces that are orthogonal to the direction of pressure contact,

an adjustment unit being inserted into one of the opposed surfaces, and

the movable holding section and the stationary holding section being arranged in such a manner that an extremity of the adjustment unit contacts the other of the opposed surfaces.

2. The transfer device according to claim 1 , wherein the controller is provided only at one end of the transfer roller in the axial direction, and the opposed surfaces of the movable holding section and the stationary holding section are arranged, in an initial state, opposite each other with a space therebetween.

3. The transfer device according to claim 1 , wherein the stationary holding section is adjacently arranged outside of the movable holding section in the axial direction of the transfer roller, and the adjustment unit is inserted into the one of the opposed surfaces in correspondence with a center axis of the transfer roller and in parallel with the elastic member.

4. The transfer device according to claim 1 , wherein the controller is provided at an axial end on a front of the transfer device.

5. The transfer device according to claim 1 , wherein the stationary holding section further includes a positioning member that performs positioning operation with respect to an image carrier on a surface of which a toner image to be transferred to the belt-shaped intermediate transfer member is made.

6. An image forming apparatus comprising:

a transfer device comprising:

a rotatable transfer roller capable coming into pressure contact with a belt-shaped intermediate transfer member; and

a controller that is provided at an end of the transfer roller in an axial direction thereof and that controls a balance of a pressure contact force exerted on the transfer roller in the axial direction,

the controller including: a bearing member that rotatably supports the end of the transfer roller in the axial direction; a movable holding section that holds the bearing member by way of an elastic member forced in a direction of pressure contact and is able to move along the direction of pressure contact; and a stationary holding section that has a guide section for guiding the movable holding section in the direction of pressure contact and that holds the movable holding section so as to be relatively movable,

the movable holding section and the stationary holding section opposing each other by way of opposed surfaces that are orthogonal to the direction of pressure contact,

an adjustment unit being inserted into one of the opposed surfaces, and

the movable holding section and the stationary holding section being arranged in such a manner that an extremity of the adjustment unit contacts the other of the opposed surfaces; and

an image forming unit that forms an image on a recording medium.