Image forming apparatus

1. An image forming apparatus comprising:

two tension rollers;

a conveyor belt movably supported by the two tension rollers;

a plurality of transfer parts that are arranged, with a recording medium conveying side of the conveyor belt as the front surface, on a back surface side of the conveyor belt and between the two tension rollers, and that contact one surface of the back surface of the conveyor belt, a predetermined clearance being formed between the transfer parts and an opposite portion of the back surface of the conveyor belt; and

a cleaning blade for removing residual toner remaining on the conveyor belt, the cleaning blade being arranged at a position where the front end of the cleaning blade contacts the conveyor belt at a predetermined pressure and the back surface of the conveyor belt distorted by the front end does not contact the tension roller;

wherein the transfer parts are arranged at a position at which they do not contact the opposite portion of the back surface of the conveyor belt distorted by a bent cleaning blade when the cleaning blade is bent in the advancing direction of the conveyor belt.

2. An image forming apparatus comprising:

two tension rollers;

a conveyor belt movably supported by the two tension rollers;

a plurality of transfer parts that are arranged, with a recording medium conveying side of the conveyor belt as the front surface, on a back surface side of the conveyor belt and between the two tension rollers, and that contact one surface of the back surface of the conveyor belt, a predetermined clearance being formed between the transfer parts and an opposite portion of the back surface of the conveyor belt;

a cleaning blade for removing residual toner remaining on the conveyor belt, the cleaning blade being arranged at a position where the front end of the cleaning blade contacts the conveyor belt at a predetermined pressure and the back surface of the conveyor belt distorted by the front end does not contact the tension roller; and

further comprising a supporting part for supporting at least one of the transfer parts, the supporting part being interposed between the at least one of the transfer parts and the cleaning blade.

3. The image forming apparatus of claim 2 , wherein the supporting part is not arranged at a position facing a portion of the back surface side of the conveyor belt at a contacting position of the front end of the cleaning blade which contacts the conveyor belt, and is arranged so that there is a clearance shorter than a free end length of the cleaning blade between the supporting part and the opposite portion of the back surface of the conveyor belt.

4. The image forming apparatus of claim 2 , wherein the supporting part is not arranged at a position facing a portion of the back surface side of the conveyor belt at a contacting position of the front end of the cleaning blade which contacts the conveyor belt, and is arranged at a position facing a portion of the back surface side of the conveyor belt at a contacting position of the front end of a bent cleaning blade which contacts the conveyor belt when the cleaning blade is bent in the advancing direction of the conveyor belt.

5. The image forming apparatus of claim 2 , wherein the supporting part is not present within twice an offset amount F from point A, where point A is a point at which the conveyor belt separates from the tension roller, and the offset amount F is a distance in the advancing direction of the conveyor belt from point A to the front end of the cleaning blade when the cleaning blade is not touching (pressing) the conveyor belt.