Image forming apparatus, cartridge, storage device and developer supplying method

1. An image forming apparatus comprising:

a developing apparatus configured to form a developer image;

a supply apparatus configured to supply developer to the developing apparatus;

a detector configured to detect an amount of developer consumed during an image forming process; and

a controller configured to perform an addition calculation for the amount of developer consumed, and for employing a value obtained by the addition calculation and a supply threshold value to determine whether developer should be supplied to the developing apparatus,

wherein the controller sets the supply threshold value in accordance with an operating state of the developing apparatus and a remaining life of the developing apparatus.

2. The image forming apparatus according to claim 1 , wherein when the value obtained by the addition calculation is greater than the supply threshold value, the supply apparatus replenishes the developing apparatus with an amount of the developer equivalent to the supply threshold value.

3. The image forming apparatus according to claim 1 , further comprising a temperature/humidity detector,

wherein the controller employs detection results obtained by the temperature/humidity detector to designate the supply threshold value.

4. The image forming apparatus according to claim 1 , wherein the detector employs a printing ratio to detect the amount of the developer consumed during the image forming process.

5. The image forming apparatus according to claim 1 , the remaining life of the developing apparatus is obtained from a limit number of prints for a life of the developing device and a current print count.

6. A detachable cartridge configured to be utilized in an image forming apparatus that includes a supply apparatus for supplying developer to a developing apparatus, and a detector for detecting an amount of developer consumed during an image forming process, the cartridge comprising:

a developing apparatus configured to hold developer; and

a storage device configured to store information, wherein the storage device includes,

a first storage area configured to store information related to a value obtained by performing an addition calculation for the amount of developer consumed;

a second storage area configured to store information related to a supply threshold value used for controlling an operation performed by the supply apparatus; and

a third storage area configured to store information used to correct the supply threshold value,

wherein the information used to correct the supply threshold value is a correction coefficient to be determined in accordance with an operating state of the developing apparatus and a remaining life of the developing apparatus.

7. A cartridge according to claim 5 , further comprising an image bearing member on which an image is to be formed.

8. A storage device adapted to be mounted on a cartridge used in an image forming apparatus that includes a supply apparatus for supplying developer to a developing apparatus, and a detector for detecting an amount of developer consumed during an image forming process, the storage device comprising:

a first storage area configured to store information related to a value obtained through an addition calculation performed for the amount of developer consumed;

a second storage area configured to store information related to a supply threshold value used to control an operation performed by the supply apparatus; and

a third storage area configured to store information for correcting the supply threshold value,

wherein the information for correcting the supply threshold value is a correction coefficient to be determined in accordance with an operating state of the developing apparatus and a remaining life of the developing apparatus.