Patent ID: 8249471

Claim:
An image forming apparatus comprising: an image forming unit configured to transfer toner onto a recording medium to form an image thereon; a toner container configured to collect toner not transferred on the recording medium; a driving force supplying unit configured to supply a driving force; a toner conveying unit configured to receive the driving force from the driving force supplying unit and move to convey the toner accumulated in the toner container; a first moving member that is provided in conjunction with the toner container and moves in accordance with the movement of the toner conveying unit; a second moving member that is provided in conjunction with the toner container and moves in accordance with an amount of the toner accumulated in the toner container, the toner conveying unit conveying the toner toward the second moving member; a detecting unit configured to output a detection signal that changes depending on the movements of the first moving member and the second moving member; and a determining unit configured to determine, based on the detection signal, whether at least one of the driving force supplying unit and the toner conveying unit is in an abnormal condition and whether the amount of the toner accumulated in the toner container has reached a predetermined accumulation level, wherein the detecting unit comprises a light emitting portion configured to emit a light and a light receiving portion configured to receive the light emitted from the light emitting portion, a light path being formed between the light emitting portion and the light receiving portion, wherein the first moving member comprises a first shielding section configured to periodically move between a first position blocking the light path and a second position allowing the light path to be formed between the light emitting portion and the light receiving portion, and wherein the second moving member comprises a second shielding section configured to integrally move with the first shielding section between a third position blocking the light path and a fourth position allowing the light path to be formed between the light emitting portion and the light receiving portion if the amount of the toner accumulated in the toner container fails to reach a predetermined accumulation level, and configured to separate from the first shielding section and to be positioned at the fourth position if the amount of the toner accumulated in the toner container has reached a predetermined accumulation level.